JP5346378B2 - Drag head for trailing suction hopper dredger and dredging method using this drag head - Google Patents

Description

Detailed Description of the Invention

  The present invention relates to a drag head of a trailing suction hopper dredger comprising a visor that is dragged at the bottom of the water to soften the soil and a suction pipe that is connected to the visor and discharges the softened soil. The present invention further relates to a method for dredging earth and sand using this drag head.

  The drag head described in the introduction is known from EP 0 892 116 A1. EP-A-0 922 116 describes a drag head for a trailing suction hopper dredger with a visor connected to a suction pipe and opened towards the bottom of the water for dredging. The visor is fixed to the trailing suction hopper dredger by a drag pipe. A plurality of teeth are installed on the visor. At dredging, the drag head, along with the drag pipe and suction pipe, is lowered into the water, generally at an oblique angle, using a winch provided at the rear of the trailing suction hopper dredger until the drag head contacts the bottom of the water. When the trailing suction hopper dredger sails, the drag head is dragged in the water, and the earth and sand are softened by the teeth meshing with the bottom. The softened earth and sand are sucked through a suction pipe and sent to, for example, a storage space of a trailing suction hopper dredger. At drought time, the drag head applies pressure to the bottom of the water because the components located in the water have a relatively large leaf weight and optionally a suction force is generated by the suction pipe. The weight of the relevant component in water corresponds to the weight of this component on land minus the weight of the water displaced by the component. Thus, the weight of steel components in water reaches about 7/8 of the weight on land (the relative specific gravity of steel is approximately 8).

  Although known drag heads have reasonable efficiency, there is a great need to further improve this efficiency. In the context of the present application, efficiency means the volume of earth and sand drowned per unit time.

  An object of the present invention is to provide a drag head for a trailing suction hopper dredger capable of dredging underwater sediment with higher efficiency than before.

  In order to achieve this object, the drag head according to the present invention has a drag head visor including at least two pressure elements that are individually movable in a direction transverse to the drag direction. A plurality of penetrations that transmit force to the bottom of the water under the influence of weight are provided. This individually movable pressure element aligned laterally to the drag direction ensures that the penetrator maintains better contact with the bottom even if the bottom is not flat. Existing drag heads have a relatively large number of penetrations. Under the condition that the bottom of the water is not flat, it is quite possible that only a very small number of these penetrators are in contact with the bottom of the water and the entire weight of the drag head is distributed over the few penetrators. Under such circumstances, the penetrator is subject to relatively large forces, and as a result is prone to failure and / or premature wear. The drag head of the present invention solves this and other problems. Not only does the average number of penetrators in contact with the water bottom (not flat) increase, but the number of penetrators per pressure element can be easily adjusted without changing the total number of penetrators. become. Because the forces on the penetrator are better distributed, it is also possible to design the drag head to be larger and heavier overall (e.g., 100 tons on land) compared to conventional cases so far. (Known drag heads generally have a weight on land of 20 to 30 tons). Using heavier and larger drag heads greatly increases dredging efficiency. In one embodiment of the drag head of the present invention, if desired, the number of penetrations may be greater than the number of penetrations in a known drag head. Using a larger number of penetrations results in a shallower average penetration depth into the bottom of the water. Surprisingly, the efficiency drop expected to occur by doing this is fully compensated by applying individually movable pressure elements.

  In a preferred embodiment, the drag head according to the invention is characterized in that the pressure element is housed in the visor by guiding means so that the pressure element can translate in a direction substantially perpendicular to the bottom of the water. And Such a variant has the advantage that almost all the weight of each pressure element is utilized. This is because, in this modification of the embodiment, each pressure element can move almost freely (in the direction perpendicular to the bottom of the water (except for frictional force and the like)).

  Yet another preferred embodiment relates to a drag head provided with a disk-like penetration, which is subject to a force through its peripheral edge under the influence of the weight of the pressure element that houses the penetration. To the bottom of the water. The disc-shaped penetration body is preferably arranged so that its disc surface is substantially perpendicular to the lower surface of the pressure element, and a part of the disc-shaped penetration body protrudes from this lower surface, so that the peripheral edge contacts the water bottom. Thus, the weight of the associated pressure element located in the water of the hopper dredger is distributed and applied to the contact surface between the penetrator and the bottom surface. By doing this, a higher pressure is generated locally and effectively crushes the bottom of the water, especially the relatively hard bottom.

  The drag head according to the present invention is preferably characterized in that the penetrating bodies extend in one row in a direction substantially transverse to the heel direction. Surprisingly, by arranging the disc-shaped penetrations in a row, not only the bottom of the bottom of the penetration is crushed, but also the bottom of the bottom located between the penetrations. I found out.

  The number of disc-shaped penetrations per pressure element can be selected within a wide range of upper and lower limits. The number of disc-shaped penetrations per pressure element is preferably 2 to 20, more preferably 2 to 10, most preferably 3 to 5. A particularly preferred distance in the lateral direction between two adjacent penetrations is 5 cm to 50 cm, more preferably 8 cm to 35 cm, and most preferably 10 cm to 20 cm. The number of pressure elements in the drag head according to the present invention may also be changed within a wide range of upper and lower limits. If a large number of pressure elements are provided, the average force transmitted to the bottom of the water by the penetrating body is reduced, but the contour of the bottom of the water can be traced with higher accuracy. The provision of a small number of pressure elements results in a simple structure. Good compromises are found when the number of pressure elements is between 2 and 20, more preferably between 2 and 8, most preferably between 3 and 5.

  The drag head is dragged in the water, and according to the present invention, the drag head is mainly in contact with the bottom through the penetration body, in particular the disc-like penetration body. Thus, the drag head is preferably characterized in that the disc-shaped penetration is housed in the pressure element and rotates about an axis perpendicular to the disc surface, the axis of rotation being substantially perpendicular to the drag direction. And By doing so, the thrust required to move the trailing suction hopper dredger at normal speed is greatly reduced.

  Yet another advantage of the drag head according to the present invention is that the bottom of the water can be crushed into relatively small particles of earth and sand, by which the particles of earth and sand are sucked up with high efficiency. This can be understood to mean that the concentration of the relevant particles in the sucked-up water is relatively high.

  In order to protect the disc-shaped penetration, the pressure element of the drag head is preferably provided with a plurality of teeth that extend substantially transversely to the drag direction and engage the water bottom upstream of the disc-shaped penetration in use. It has been. The teeth break a predetermined part of the bottom of the water, and then the penetrator reaches the bottom of the water. Teeth can also level the bottom of the water, which allows the disc-shaped penetrator to work with higher efficiency. By combining the teeth and the disc-shaped penetration body in this way, the efficiency can be further increased.

  A further improved drag head is obtained if the pressure element is further provided with support means for engaging the water bottom upstream of the disk-like penetration and optionally upstream of the teeth in use. If the bottom is not quite flat, this support means ensures that the pressure element and sometimes the entire visor follow the contours of the bottom. By doing so, it is possible to prevent clogging and / or breakage of the drag head, in particular the disc-shaped penetration body. In a particularly preferred embodiment, the support means comprises a plurality of sliding blocks, which are preferably installed laterally. The sliding block has a contour that allows the drag head to follow the contours of the bottom of the water instead of digging into the bottom of the water and sinking there. By doing so, the sliding block also has a protective function.

  The disc-shaped penetration body generally sinks to the bottom of the water at a certain penetration depth under the weight of the pressure element. This typical penetration depth can be determined during the design of the disk-like penetration. In a variant of the preferred embodiment, the drag head according to the invention has a tooth preferably 0.5 times to 10 times the depth of penetration of the disk-like penetration body, more preferably 0. It is characterized by meshing with the bottom of the water at a position 5 to 5 times, most preferably 0.5 to 1.5 times higher. In this way, the teeth have an optimal protective effect and the highest efficiency is achieved. The teeth also have a penetration depth. The depth of penetration of the teeth is preferably limited so as not to cause tooth breakage or excessively high cutting forces. It is preferred here that the lower surface of the support means is located above the lower surface of the tooth by a predetermined distance, preferably a limited distance. The support means is preferably positioned higher than the teeth, more preferably at a position higher by 0.5 to 1.5 times the penetration depth of the teeth, so that the support means can engage the bottom of the water. ing. By this aspect, a better protective effect can be obtained with a further improved efficiency.

  In a further improved preferred embodiment, the drag head according to the invention is provided with closing means for closing at least partly the opening between the components, in particular between the visor and the bottom of the water. Yes. By providing the closing means, the suction force supplied through the suction pipe can draw the drag head toward the bottom of the water. The generated suction forces ensure that sufficient pressure is applied to the bottom of the water under the penetrator, so that the bottom of the water breaks, breaks or otherwise collapses. Closing the opening between the visor and the bottom of the water may be accomplished in any manner known to those skilled in the art. Accordingly, the closing means comprises a strip of material that is flexible and that spans the opening and is secured to the associated component on at least one side of the opening.

The dimensions of the penetrating body are selected according to various factors such as a desired pressure and the number of penetrating bodies per pressure element. The diameter of the penetrating body may be between several centimeters and several tens of centimeters. Particularly suitable diameters are 2 cm to 80 cm, more preferably 5 cm to 60 cm, and most preferably 10 cm to 40 cm. An intruder with such a diameter has a good balance between the thrust required to move forward 1 m and the dredging efficiency to be achieved, ie the volume of earth and sand dredged per second (m ³ ). Have

  If desired, the drag head according to the invention may comprise at least one set of jet pipes for injecting water (preferably under high pressure). The pressure may be 2500 bar, but the normal pressure is, for example, in the range of about 10 bar to 200 bar. The water jet need only be directed toward the bottom of the water before, below, or after the penetrator, thereby improving dredging efficiency.

  The invention also relates to a method for crushing and / or dredging at least partially hard bottom in water using a trailing suction hopper dredger provided with a drag head according to the invention. The method includes lowering the drag head according to the present invention to the bottom and then dragging it at the bottom. Here, a suction force is applied via a suction pipe to a space that is at least partly closed via the closing means and enclosed by the visor and the bottom of the water, so that the influence of the weight of the pressure element and the suction force Underneath, the disc-shaped penetration body penetrates into the bottom of the water through its peripheral edge and causes a crack in the bottom of the water. The earth and sand crushed into chips are sucked up through a suction pipe. According to the invention, the pressure elements now move independently of one another, whereby an increase in efficiency is achieved. During drought, the pressure elements preferably translate independently of each other in a direction substantially perpendicular to the bottom of the water. In a preferred method, the pressure element support means first engages with the bottom of the water, the pressure element is forced to follow the contour of the bottom of the water, then the teeth engage with the bottom of the water and the bottom is at least partially leveled, and then The penetrating body meshes with the bottom of the water.

  Next, the drag head and method according to the present invention will be further described based on the following description of preferred embodiments and drawings, but this does not limit the present invention in any way.

  FIG. 1 shows a schematic perspective view of a drag head according to the present invention as viewed from below.

  FIG. 2 shows a schematic perspective view of the drag head of FIG. 1 as viewed from above.

  FIG. 3 shows a schematic perspective view of the pressure element of the drag head according to the invention as seen from below.

  FIG. 4 shows a schematic perspective view from above of a support structure in which the pressure element can be stored as shown in FIG.

  FIG. 5 shows a schematic view during operation of the drag head according to the present invention.

  A drag head 1 for a trailing suction hopper dredger is shown in FIG. The drag head 1 includes a visor 2 that softens the earth and sand by being dragged in the drag direction P (see also FIG. 5) at the bottom 50 of the water, and a suction pipe 3 that is connected to the visor 2 and discharges the softened earth and sand. ing. The visor 2 is provided with side walls (84, 85) and an upper plate 86 connected to the suction pipe 3. In the illustrated embodiment of the drag head according to the invention, the visor 2 comprises four individually movable pressure elements (21, 22, 23, 24) transverse to the drag direction P. The pressure elements (21, 22, 23, 24) are accommodated in the visor 2 by guide means (211, 212, 213, 214, 215, 216, 217, 218) (see FIG. 3). To achieve this purpose, the visor 2 comprises a support structure as illustrated in FIG. 4, which in the variant of the illustrated embodiment has a pressure element (21, 22, 23, 24). There are four rooms (25, 26, 27, 28) to be housed inside. The guide means includes four guide rollers (211, 212, 213, 214) disposed on the rear wall 31 of the pressure element 21 and four guide rollers (215, 216, 217) disposed on the front wall 32. 218), and each of the four guide rollers is rotatable on the corresponding rear wall 41 and front wall 42 of the room (25, 26, 27, 28). In order to prevent the pressure elements (21, 22, 23, 24) from leaving the visor 2, a stop edge (33, 34) is provided on each rear wall 31 and front wall 32 for each pressure element. . The pressure elements (21, 22, 23, 24) can thereby be translated relatively freely in a direction L substantially perpendicular to the bottom 50, and the stop edges (33, 34) can be, for example, pressure When element 21 is in the lowest position, it rests on the upper edge of room 25.

  As shown in FIG. 3 in the case of the pressure element 21, each pressure element (21, 22, 23, 24) is provided with four penetration bodies (51, 52, 53, 54). This penetrating body (51, 52, 53, 54) has a disk-like shape, and transmits force to the bottom 50 through the peripheral edge under the influence of the weight of the pressure element that houses the penetrating body. This causes a crack in the bottom of the water. In each pressure element, the disc-shaped penetration bodies (51, 52, 53, 54) extend in a row substantially in the transverse direction with respect to the drag direction P. In addition, the penetrating bodies of all the pressure elements are preferably configured to extend in a row substantially in the lateral direction with respect to the drag direction P as a whole. This configuration is shown in FIG.

  In the illustrated embodiment, the pressure elements (21, 22, 23, 24) of the drag head 1 extend substantially transversely with respect to the drag direction P, and in use, disc-shaped penetrations (51, 52, 53, 54) is further provided with a plurality of teeth (61, 62, 63, 64) that mesh with the water bottom 50 upstream. The pressure elements (21, 22, 23, 24) are further provided with support means (71, 72, 73, 74). This support means comprises a sliding block. This sliding block is for example made of steel and slanted from the front wall 32 of the associated pressure element 21 to the disc-shaped penetration (51, 52, 53, 54) and / or the teeth (61, 62, 63, 64). It has a lower surface that spreads out. In use, the support means (71, 72, 73, 74) are located upstream of the disc-shaped penetration body (51, 52, 53, 54) and, if necessary, of the teeth (61, 62, 63, 64). The upstream side meshes with the bottom of the water, so that the support means first meshes with the bottom 50. Accordingly, the associated pressure element is forced to follow the contour of the bottom 50. When the bottom 50 rises, the associated pressure element is pushed up before the teeth (61, 62, 63, 64) and the penetrator (51, 52, 53, 54) penetrate the bottom. The support means (71, 72, 73, 74) not only protect the teeth and the disc-like penetration, but also the desired penetration depth of the penetration (51, 52, 53, 54, 61, 62, 63, 64). Also controls. Since the teeth (61, 62, 63, 64) mesh with the bottom of the water on the upstream side of the disc-shaped penetration body (51, 52, 53, 54), the teeth similarly protect the disc-shaped penetration body, and the penetration body ( 51, 52, 53, 54) to control the desired penetration depth. The best results are achieved when the lower surface of the support means is located at a predetermined distance, preferably a limited distance, above the lower surface of the teeth. This is achieved, for example, when the teeth (61, 62, 63, 64) have a penetration depth and the support means is 0.5 to 1.5 times the penetration depth of the teeth than the teeth. Only when engaged with the bottom 50, and when the disc-shaped penetration body (51, 52, 53, 54) has a penetration depth and the teeth (61, 62, 63, 64) have a disc-shaped penetration This is a case where it engages with the water bottom 50 at a position higher by 0.5 to 1.5 times the penetration depth of the disc-shaped penetration body than the body.

  For example, in the embodiment of the drag head 1 illustrated in FIG. 1, the visor 2 may have a visor 2 and a bottom 50 to eliminate the possibility of supply water being supplied along a relatively unproductive side of the visor 2. Closing means are provided for substantially closing the opening between the two. This closure means is disposed on both side walls (84, 85) and is slidable in the height direction, if desired, a closure plate (81, 82) with a rubber covering layer on the lower edge It has. The visor 2 is provided with a collar plate 83 on the lower surface on the upstream side, which provides sufficient support on the bottom 50 and prevents water from being drawn in along the upstream side.

  At the time of dredging, the reduced pressure state is maintained inside the drag head 1 so that the softened hard earth and sand particles and other earth and sand particles can be sucked up through the suction pipe 3. Referring to FIG. 5, in the method according to the present invention, the drag head 1 is lowered to the bottom 50, and the drag head 1 is dragged in the drag direction P at the bottom 50. Here, a suction force is applied by the suction pipe 3 to the space that is at least partly closed via the closing means (84, 85) and is enclosed by the visor 2 and the water bottom 50, and thus, a disc-like shape. Under the influence of the weight of the pressure element that accommodates the penetrating body (51, 52, 53, 54), the penetrating body (51, 52, 53, 54) is penetrated into the bottom 50 through its peripheral edge to enter the bottom of the water. Generate cracks. By applying a large number of disc-shaped penetrations (51, 52, 53, 54) arranged adjacent to each other, the bottom of the water located between the penetrations is also crushed, thereby increasing the efficiency. Was found to be considerably higher. Chip-like earth and sand produced by crushing the bottom of the water is sucked up through the suction pipe 3. According to the invention, the pressure elements (21, 22, 23, 24) are here translated in a direction substantially perpendicular to the bottom 50 and almost independently of each other. This maintains a large number of penetrators in contact with the bottom 50, which improves efficiency despite the possibility of a lower average penetration depth compared to the prior art. To do. Support means (71, 72, 73, 74) first engage with the bottom 50 and provide, for example, protection against the penetrating body. Even higher efficiencies are achieved by applying a combination of teeth and disc-shaped penetrations. In this case, first, the teeth mesh with the bottom of the water to a predetermined penetration depth to at least partially level the bottom 50, and then the disc-shaped penetration body meshes with the bottom 50. In addition, it is also preferable to install a drag head in which the disk-like penetration body first meshes with the bottom of the water to a predetermined penetration depth and at least partially crushes the bottom 50, and then the teeth mesh with the bottom 50.

  The invention is not limited to the embodiments described above by way of example, and modifications to the invention are possible and these modifications do not depart from the scope of the appended claims.

It is the schematic perspective view which looked at the drag head concerning the present invention from the bottom. It is the schematic perspective view which looked at the drag head of FIG. 1 from the top. It is the schematic perspective view which looked at the pressure element of the drag head concerning the present invention from the bottom. It is the schematic perspective view which looked at the support structure which a pressure element can accommodate as shown in FIG. 3 from the top. It is the schematic in operation | movement of the drag head which concerns on this invention.

Claims (16)

Dragging of a trailing suction hopper dredger comprising a visor (2) that is dragged at the bottom of the water (50) to soften the earth and sand, and a suction pipe (3) that is connected to the visor (2) and discharges the softened earth and sand. Head (1),
The visor (2) comprises at least two individually movable pressure elements (21, 22, 23, 24) transverse to the drag direction;
Each of the pressure elements is provided with a plurality of penetrating bodies (51, 52, 53, 54, 61, 62, 63, 64) that transmit force to the water bottom (50) under the influence of the weight of the pressure element. The drag head is characterized by that.   The pressure elements (21, 22, 23, 24) are guided by means (211, 22, 23, 24) so that the pressure elements (21, 22, 23, 24) can translate in a direction substantially perpendicular to the water bottom (50). 212. Drag head according to claim 1, characterized in that it is housed in the visor (2) by 212, 213, 214).   The penetrator includes disk-like penetrators (51, 52, 53, 54) that transmit force to the bottom (50) via the peripheral edge (23) under the influence of the weight of the pressure element. The drag head according to claim 1, wherein the drag head is provided.   4. Drag head according to claim 3, characterized in that the disc-shaped penetration bodies (51, 52, 53, 54) extend in a row substantially transversely to the heel direction.   The number of disc-shaped penetration bodies (51, 52, 53, 54) per said pressure element is 2 to 10, more preferably 3 to 5, characterized in that The drag head according to any one of the above.   The number of the pressure elements (21, 22, 23, 24) is 2 to 8, more preferably 3 to 5, according to any one of claims 1 to 5. Drag head.   The pressure element (21, 22, 23, 24) extends substantially transversely to the drag direction, and the water bottom (50) is located upstream of the disc-shaped penetration (51, 52, 53, 54) in use. The drag head according to claim 1, wherein a plurality of teeth (61, 62, 63, 64) that mesh with the drag head are provided.   The pressure elements (21, 22, 23, 24) include upstream of the disc-shaped penetration (51, 52, 53, 54) and optionally teeth (61, 62, 63, 64) in use. 8. Drag head according to any one of the preceding claims, characterized in that on the upstream side, support means (71, 72, 73, 74) are provided which mesh with the water bottom (50).   9. Drag head according to claim 8, characterized in that the support means (71, 72, 73, 74) comprise a sliding block. The disc-shaped penetration body (51, 52, 53, 54) has a penetration depth,
The drag head according to any one of claims 7 to 9, characterized in that the teeth (61, 62, 63, 64) mesh with the bottom of the water at a position higher than the disc-shaped penetration body. The teeth (61, 62, 63, 64) have a penetration depth;
11. Drag head according to any one of claims 8 to 10, characterized in that support means (71, 72, 73, 74) mesh with the bottom (50) at a position higher than the teeth.   The drag head (1) is provided with closing means (81, 82) for substantially closing an opening between the visor (2) and the water bottom (50). The drag head according to any one of 1 to 11.   The drag head according to claim 1, wherein the drag head comprises at least one set of jet pipes for injecting water under high pressure. Using the trailing suction hopper dredger provided with the drag head according to any one of claims 1 to 13, a method of drowning the water bottom that is at least partially hard in water,
The drag head is lowered to the bottom of the water and dragged by the bottom of the water,
A suction force is applied via the suction pipe to the space that is at least partially closed via the closing means and enclosed by the visor and the water bottom, and under the influence of the weight of the pressure element and the pressure reduction, the disc A penetrating intrusion into the bottom of the water through its peripheral edge to generate a crack in the bottom of the water,
A method characterized by sucking up the earth and sand crushed into chips through the suction pipe.   15. The method according to claim 14, characterized in that, when dredging, the pressure elements translate in a direction substantially perpendicular to the bottom of the water independently of each other. First, the support means of the pressure element meshes with the water bottom,
The pressure element is forced to follow the contours of the bottom,
Thereafter, the teeth mesh with the bottom and the bottom is at least partially leveled,
16. The method according to claim 14 or 15, further characterized in that after that, the penetrating body engages the bottom of the water.

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