KR101697622B1 - Cutter head for dredging ground, cutter suction dredger provided with such a cutter head and use of the cutter head for dredging ground - Google Patents

Abstract

The present invention relates to a cutter head 10 for dredging a ground below a water surface, the cutter head being rotatably attached about a central axis with respect to the ladder 2 of the cutter suction dredger 1, The cutter head being adapted to move therethrough along with the ground, the cutter head comprising a base ring (13), a hub (14) positioned away from the base ring in a central axial direction, and a plurality of support arms The passage openings 16 are located between the support arms and the cutting tools 20 are at least asymmetric at their free outer ends. The inventive cutter head has an increased efficiency, especially for lands having a uniaxial compressive strength (UCS) of at least 50 MPa.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutter head for dredging the ground, a cutter suction dredger provided with such a cutter head, and a cutter head for dredging the ground. dredging ground}

The present invention relates to a cutter head for dredging a soil in water, which is attached to a ladder of a cutter suction dredger and, together with a lateral sweeping movement, It is suitable for moving on the stomach. The present invention also relates to the use of a cutter suction dredger provided with such a head and a cutter head for dredging the ground, in particular relatively hard land.

Cutter heads of the type described in the opening paragraph are known, for example, from NL 1031253. The known cutter head is a rotatable body which is rotatable around a central axis and is formed by a base ring and a hub disposed at a distance from it and concentrically disposed thereon, Between the hubs there are a multiplicity of support arms to which the cutting tools are provided. Known cutting tools are bit-like, meaning that they contain flat portions at their free outer ends and that at their end surfaces they contact the ground over a determined linear distance. For good cutting action, the cutting tools must first contact the ground during rotation of the known cutter head. Therefore, the cutting tools are positioned above the leading portion of the support arms when viewed in the direction of rotation of the cutter head.

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The known cutter head is a land with an unconfmed compressive strength (UCS) of at least 50 MPa, which is relatively hard soils as defined in the context of the present application, for example, rocks that can not be dredged or only dredged with limited efficiency I have a problem. The UCS is a concept known to those skilled in the art and represents the compressive strength of a ground mass whose sidewalls are not supported during compression. Efficiency is understood to mean the volume of land dredged per unit time and unit force in the context of this application.

It is an object of the invention to provide a cutter head for a cutter aspiration dredger which, in addition to other advantages, enables more efficient dredging of the surface of the ground, and in particular of a relatively hard form of land, .

According to the invention, a cutter head provided for this purpose comprises a rotating body rotatable about a central axis and formed by a base ring and a hub located away therefrom, and cutting tools are provided between the base ring and the hub A plurality of support arms extend and the cutter head includes at least 50 cutting tools and the cutting tools are at least asymmetrical along their entire length at their free outer ends, A cutter head is provided that allows free rotation about an axis. It has been found that by providing the support arms of the cutter head with cutting tools which are asymmetrical, especially on the soil contact side of the support arms, relatively hard land, such as rocks, can be dredged with increased efficiency for known cutter heads . The asymmetry of the cutting tools has been found to have the desired effect in the destruction of the soil, in particular the relatively hard soil.

Known cutting tools are relatively wide at their free outer ends to withstand the great forces they receive during dredging. The weight of the underwater components of the cutter aspiration dredge eventually distributes over the contact surfaces between the cutting tools and the ground. By providing a relatively wide free outer end to a known cutting tool, such a contact surface is relatively wide, so that the forces transmitted to the ground are distributed over a relatively large surface area. Thus, the average pressure on the contact surface is kept limited, thereby preventing breakage of the cutting tools.

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A preferred embodiment of the cutter head is characterized in that the cutting tools are rotational-symmetrical and more preferably conical. Such a geometry allows for higher average pressures to be transmitted to the ground than is possible by known cutting tools. Another advantage of the preferred embodiment of the cutting tool, in particular the conical shape, according to the present invention is that it takes up less space than a known cutting tool due to its shape. As a result, it becomes possible to provide a large number of cutting tools to the cutter head, which has been found to be advantageous for the dredging efficiency of the cutter head. For the same reasons, the passage openings that exist between the support arms of the cutter head and through which the dredged soil is discharged may be smaller than those of the known cutter head. This is because the cutting tools according to the present invention are less likely to obstruct the passage. As a result, the number of support arms can also increase.

According to another best embodiment of the present invention, the cutting tools comprise a substantially cylindrical body portion having a reduced diameter relative to the conical top portion. The cutting tool according to this embodiment is arranged with the cylindrical body portion of the cutting tool in the engaging means provided on the arms of the cutter head. The engaging means preferably includes a block socket having a central bore into which the cylindrical body portion is inserted for ready rotation. In this embodiment, the conical portion will protrude out of the block socket over an active length that is relatively short compared to the overall length of the cutting tool. This has the advantage that it can withstand much more forces than with cutting teeth at the cutting edge. In addition, the block socket efficiently supports the cutting tool against bending deformations. In a preferred embodiment, the cutting tools have a length that protrudes out of its holder between 10 and 500 mm, more preferably between 20 and 250 mm, most preferably between 50 and 150 mm .

In a particularly preferred embodiment, the cutting tool is arranged in the socket so as to be freely or at least easily rotatable about its rotational-symmetry axis. This is possible due to the fact that the cutting tools are rotationally symmetric. Allowing freedom or ready rotation of the tools during operation reduces the risk of fracture and also self-sharpens the soil-contacting tip of the cutting tools by friction with the soil. Thus, the useful life of the cutting tools is prolonged and precious time is saved by not frequently replacing broken or dull cutting tools.

The conical portion of the cutting tool is preferably provided with a curing tip at the outer end in contact with the soil. The tip can be made, for example, of carbide.

In another preferred embodiment, the cutter head according to the invention is characterized in that the upper part of the conical cutting tools is at most 500 mm, more preferably at most 350 mm, even more preferably at most 100 mm, and most preferably at most 50 mm And has a radius of curvature. Another preferred variant comprises conical cutting tools, the upper part of which has a radius of curvature between 1 and 100 mm, and more preferably between 5 and 80 mm. In another preferred variant, the cutting tools comprise a holder in which a conical hard metal insert is received.

A preferred embodiment of the cutter head according to the invention is characterized in that the cutter head comprises at least five support arms, more preferably at least 10 support arms, and more preferably at least 15 support arms. The cutter head is even possible to include a rotating surface provided with passage openings between the base ring and the hub. The portion of the rotating surface that lies between the openings then forms the " support arms " of the cutter head. Another option is to provide a cutter head having axially extending support arms on which transverse arms extending in a circumferential direction are mounted.

The number of cutting tools can be varied within wide limits, where the number of cutting tools is advantageous as much as possible. In a preferred embodiment, the cutter head according to the invention comprises at least 100 cutting tools, more preferably at least 140 cutting tools, and most preferably at least 180 cutting tools. Wherein the cutting tools may be distributed regularly across the rotating surface of the cutter head, but may also be distributed irregularly. The number of cutting tools per support arms is at least 10 cutting tools, more preferably at least 15 cutting tools, even more preferably at least 20 cutting tools, and most preferably at least 25 cutting tools .

The cutter head according to the present invention cuts the ground in a fundamentally different manner than a known cutter head. If a known cutter head strikes a large piece of ground with great force, the cutter head according to the invention will break down much smaller operations of the ground. Due to the greater number of cutting tools in the direction of rotation of the cutter head, the ground is cut more rapidly in succession. It has been found that this operation results in higher efficiency, especially in harder grounds.

It is advantageous for the support arms to include a first series of cutting tools on the leading portion when viewed in the direction of rotation of the cutter head and to include a second series of cutting tools on the at least one support arm deviating from the central axis It was also discovered. Although it is unusual to provide cutting tools on the portion of the support arm deviating from the central axis, improved efficiency is obtained. Surprisingly, it has been found that the connection of the cutting tools to the part of the support arm deviating from the central axis is strong enough to transmit forces to the support arm due to the cutting tools impacting particularly hard ground such as rocks. More cutting tools can be placed in this manner on a single support arm according to the prior art. This is particularly advantageous for dredging relatively hard land.

In an advantageous embodiment, a first series of cutting tools on the support arm is offset relative to a second set of cutting tools. This further increases dredging efficiency. Since the cutting tools are offset, an increased working area of the cutting tools is obtained. This is because the second series of cutting tools is not disturbed by the first series of cutting tools.

In yet another embodiment, the support arms have a length and the cutting tools are positioned on both sides of the middle of the support arms according to up to 80% of the length of the support arm. The absence of the cutting tools near the outer ends of the support arms has not been found to adversely affect the efficiency of the cutter head, and this approach results in simpler and therefore cheaper construction of the cutter. On the other hand, the presence of cutting tools near the hub of the cutter head is advantageous for the progression of the cutter head.

The cutting tools may be integrally formed with the support arms of the cutter head. Another way is to connect them directly to the support arms by, for example, welding the cutting tools substantially embodied in steel to the support arms which are made substantially steel, which results in a strong connection. The cutting tools can be connected to the support arms, in particular via the coupling means. As a result, the exchange of cutting tools, which may be necessary as a result of wear or tear, can be facilitated. Here it may be advantageous, for example, to connect the coupling means itself together with the support arms using a weld connection.

In a preferred embodiment of the cutter head according to the present invention, the support arms of the cutter head are provided with guides in which coupling means and / or cutting tools are displaceably mounted. Suitable guides include, for example, coupling means and / or guide rails on which the cutting tools can slide. This preferred variant has the advantage that the coupling means and / or the cutting tools can be easily displaced. Thus, the intermediate distance between cutting tools can be adjusted in a simple manner, depending on the properties of the soil, especially the hardness.

The present invention also relates to a method for cutting land with unconfined compressive strength (UCS) between 50-200 MPa, preferably between 60-150 MPa and most preferably between 80-100 MPa, To the use of a cutter head according to the present invention. With reference to the advantages already mentioned above of the cutter head according to the invention for the advantages of the use of the cutter head.

The present invention also relates to a cutter suction dredger provided with a cutter head according to the present invention. By means of the cutter suction dredger provided with the cutter head according to the invention, land and, in particular, relatively hard land, i.e. land with UCS greater than 50 MPa, can be dredged with improved efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be further described with reference to the following description of preferred embodiments and the following drawings, but the invention is not limited thereto. The drawings are not necessarily drawn to the same scale.

1 is a schematic side view of a cutter suction dredger portion having a ladder provided with a cutter head according to the present invention and attached to a cutter suction dredger.
2 is a perspective view of a cutter head according to the present invention;
3 is a side view of a detail of a cutting tool according to the present invention;
4 is a side view of a detail of a cutting tool according to another embodiment of the present invention;
5 is a side view of a detail of a cutting tool according to another embodiment of the present invention;

Fig. 1 shows a cutter suction dredger 1 in which a ladder 2 is pivotally mounted around a horizontal shaft 3. The ladder (2) is provided with a suction pipe (4) through which loose land portions can be sucked up to a height above the water surface (100) and from which they are discharged. The ladder 2 is arranged on the deck of the cutter aspiration dredger 1 and is used for dredging or destroying by a winch 5 provided with a number of swing winches (not shown) and a ladder winch 8 Pull over the ground surface (9). The ladder 2 is provided on its outer end with a cutter head 10 according to the present invention. The cutter head 10 can be lowered into the water by the ladder winch cables 8 and moved from the port side in use on the ground surface 9 to the starboard side of the cutter suction dredger 1, Conversely, it is moved to reciprocating, sweeping motion. In order to be able to absorb the forces generated here on the ground surface, the cutter suction dredger 1 is anchored to the ground by a spud post 101. 1 shows the left (starboard) spud post of an unanchored position and the right (port side) spud post of an anchored position.

Referring to Fig. 2, the cutter head 10 according to the present invention includes a rotating body 11 that can be set to rotate around the rotational axis 12 of the rotating body by driving means (not shown). Here, the rotary shaft 12 coincides with the center axis of the cutter head 10. In the illustrated embodiment, the rotating body 11 is set to rotate in the clockwise direction R viewed from the bridge. The support arms 15 extend spirally between the base ring 13 and the hub 14 located away from the base ring 13 and these support arms 15 extend between the base ring 13 and the hub 14 . The support arms 15 are arcuate here and the convex sides are oriented in the direction of rotation R. [ The base ring 13, the hub 14 and the support arms 15 are made substantially of steel. This not only strengthens the cutter head 10 but also imparts a greater weight to the cutter head 10 so that the cutter head 10 during dredging is subjected to gravity and urged in the direction of the ground for dredging ). The support arms 15 are regularly arranged around the circumference of the cutter head 10 here. The passage apertures 16 are located between the support arms 15. The engaging means 17 made of substantially steel are arranged in the same direction as the support arms 15 with respect to the direction of rotation of the cutter head 10 to engage the first series of cutting tools with the support arms 15. [ And is welded to a leading edge 15a. The engaging means 17 which are likewise made substantially rigid are likewise provided with support arms 15 which deviate from the central axis of the cutter head 10 to engage the second series of cutting tools 20 with the support arms 15 (15b). The engaging means 17 are oriented such that the front or striking side of the first and second series of cutting tools 20 is oriented in the rotational direction R. [

In Fig. 3, an embodiment of a cutting tool 20 is shown. The illustrated cutting tool 20 having an overall length 27 comprises a generally cylindrical portion 22 of diameter 25 and a conical second portion 23. [ The cutting tool 20 may be provided with a cylindrical portion 22, for example by means of a snap connection 220, on the aforementioned engagement means of the cutter head 1. Permanent connections are also possible, or other types of releasable connections are possible. In the situation where the cutting tool 20 is arranged in the coupling means 17 the conical portion 23 will project beyond the active length 26 and out of the coupling means or holder 17. [ The conical portion 23 of the cutting tool 20 is provided with a hardened tip 28 at the outer end which will come into contact with the soil. The appropriate radius of curvature of the tops of the cutting tools 20 depends on the specific characteristics of the ground and other cutter heads of other factors, but preferably lies between 1 and 200 mm. The appropriate overall length 27 of the cutting tool 20 is preferably between 20 and 400 mm. A suitable transverse dimension 25 is preferably between 10 and 200 mm. In a preferred embodiment, the cutting tool 20 has a length 26 between 10 and 500, more preferably between 20 and 250 mm, most preferably between 50 and 150 mm and protruding beyond the holder 17 I have.

4 and 5, the cutting tool 20 is preferably a block socket having a central core 170 into which a cylindrical shank part of the cutting tool 20 is inserted for ready rotation, is coupled to the support arms (15) through a coupling means (17) in the form of a block socket. In the embodiment of Figure 4, the conical portion 23 with carbide tips 28 protrudes beyond the short effective length relative to the overall length of the cutting tool 20 to the outside of the block socket. The block socket 17 supports the cutting tool 20 for bending deformations and allows to transmit large compressive forces in the axial direction 171 of the cutting tool 20. The cutting tool 20 is inserted into the central bore 170 from the left until the snap connection 220 engages the corresponding annular groove 221 in the socket. In the combined state, the cutting tool 20 is free to rotate about the axis 171 of the central bore 170 due to the fact that the cutting tool 20 is rotationally symmetric. This rotation may be somewhat hindered by frictional forces between the outer surface of the body portion 22 and the inner portion of the central bore 170 or between the contact surfaces of the socket and the conical portion 23, but free rotation is essential .

Another embodiment shown in Fig. 5 uses a separate holding ring 172 with a slot 173 so that it can be compressed and made smaller. Once engaged with the corresponding annular groove 221 (such as in the embodiment shown in FIG. 4), it remains on the outer surface of the body portion 22 to expand and rotate freely. Locking of the cutting tool 20 in the axial direction 171 is achieved by engagement of the rear portion 222 of the cutting tool 20 with respect to the annular ring 172.

The cutter head according to the invention is particularly suitable for destroying relatively hard land, self-sharpening and has an extended service life.

Claims (13)

A cutter head (10) for dredging a land under a water surface,
And a rotating body (11) rotatable about a central axis of the cutter head (10) and formed by a base ring (13) and a hub (14) positioned away from the base ring (13) A plurality of support arms 15 with cutting tools 20 extend between the support arms 15 and the passage openings 16 are provided between the support arms 15 for the discharge of dredged soil And the cutter head 10 comprises at least 50 cutting tools,
Wherein one end of the cutting tools (20) is axially symmetric about an axis of symmetry (171) of the cutting tool (20). The method according to claim 1,
Characterized in that the cutting tools (20) are arranged on the support arms (15) so as to freely rotate about the axis of symmetry. The method according to claim 1,
Characterized in that the cutting tools (20) are conical. The method according to claim 1,
Characterized in that one end of the cutting tools (20) is a conical shape with a radius of curvature of at most 50 mm. The method according to claim 1,
Characterized in that the cutter head (10) comprises at least ten support arms (15). The method according to claim 1,
Characterized in that the support arms (15) each comprise at least 20 cutting tools (20). The method according to claim 1,
Characterized in that the cutting tools (20) are oriented with respect to the support arms (15) such that the cutting tools (20) collide with the ground surface during rotation of the cutter head through the ground (10). The method according to claim 1,
The support arm 15 includes a first set of cutting tools 20 on the leading edge 15a of the support arm 15 and a second set of cutting tools 20 on the edge 15b of the support arm 15. The support arm 15 includes a first set of cutting tools 20 on the leading edge 15a of the support arm 15, Characterized in that it comprises a series of cutting tools (20). 9. The method of claim 8,
Characterized in that the first series of cutting tools (20) are offset relative to the second series of cutting tools (20) along the longitudinal direction of the support arm (15) Cutter head (10). The method according to claim 1,
Characterized in that the cutting tools (20) are connected to the support arms (15) via coupling means (17). 11. The method of claim 10,
Characterized in that the support arms (15) of the cutter head are provided with guides on which the coupling means (17) or the cutting tools (20) are displaceably mounted. . delete A cutter aspiration dredger (1) provided with a cutter head (10) as claimed in any one of claims 1 to 11.

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