ES2391881T3 - Drag head for a pitcher dredger with suction tube and dredging procedure using this drag head - Google Patents

Abstract

Drag head (1) of a pitcher dredge with suction tube comprising a visor (2) which dragged on the bottom (50) and in that place loosen the ground and a suction pipe (3) which is connected the visor (2) and which discharges the loosened terrain characterized in that the visor (2) comprises at least individually movable pressure elements (21, 22, 23, 24) transversely to the drag direction, in which a pressure element It is provided with a series of penetration bodies (51, 52, 53, 54, 61, 62, 63, 64) which transmit forces to the bottom (50) under the influence of the weight of the pressure element.

Description

Drag head for a pitcher dredger with suction tube and procedure for dredging using this drag head.

The invention relates to a drag head of a pitcher dredge with suction tube, which comprises a visor which is dragged on the bottom and thereby loosen the ground and a suction pipe which is connected to the visor and which unloads the loosened ground. The invention also relates to a method for ground dredging using this drag head.

A drag head according to the preamble is known from EP-A-0892116. EP document

- A - 0892116 describes a drag head for a pitcher dredge with suction tube comprising a visor which is connected to a suction pipe and is open towards the bottom for dredging. The visor is fixed to the pitcher dredger with suction tube by means of a drag pipe. A series of teeth are arranged in the visor. During dredging the drag head with the drag pipe and the suction pipe is lowered below the water to a globally oblique angle with a winch at the rear of the pitcher dredger with suction pipe, until the head of Drag makes contact with the bottom. During the displacement of the pitcher dredge with suction tube, the drag head is dragged on the bottom below the water, where the ground is loosened by the teeth that are coupled at the bottom. The loosened ground is sucked through the suction pipe, for example to a storage space present in the pitcher dredger with suction pipe. During dredging, the drag head exerts pressure on the bottom due to the relatively high weight of the components located below the water and optionally due to the suction force developed by the suction pipe. The weight below the water of the relevant components corresponds to the weight above the water thereof less the weight of the water displaced by said components. The weight below water of a steel component therefore amounts to approximately 7/8 of the weight above water (the relative specific weight of steel being approximately equal to 8).

Although the known drag head has reasonable performance, there is a great need to further improve this performance. Within the context of this application, performance is understood to mean the volume of land dredged per unit of time.

The object of the present invention is to provide a drag head for a pitcher dredger with suction tube which is capable of dredging ground below water with improved performance.

This object is achieved by a drag head according to all the technical characteristics, in combination, of claim 1.

The drag head according to the invention has the characteristic that the visor of the drag head comprises at least two individually movable pressure elements transversely to the dredging direction, in which a pressure element comprises a series of bodies of penetration which transmit forces to the bottom under the influence of the pressure element weight.

Individually movable pressure elements that run transversely to the direction of drag ensure that penetration bodies are better able to maintain contact with the bottom when the bottom is not uniform. The existing drag head comprises a relatively large number of penetration bodies, in the case of non-uniform bottom conditions it is very possible that only a small number of these penetration bodies make contact with the bottom, whereby the full weight of the Drag head is distributed over a small number of penetration bodies. The penetration bodies are therefore subjected to relatively large forces which can easily result in breakage or rapid wear of the penetration bodies. The invented drag head solves this and other problems. Not only will more penetration bodies on average make contact with the bottom (not uniform), but also the number of penetration bodies per pressure element can also be quickly adjusted without changing the overall number of penetration bodies. Since the forces in the penetration bodies are better distributed, it is also possible to provide the overall drag head with a larger and heavier design (for example a weight above the water of 100 t) than what has been normal until now (The known drag head generally has a ground weight of 20-30 tons). A heavier and larger drag head will significantly increase dredging performance. In an embodiment of the invented drag head the number of penetration bodies, if desired, may be greater than in the known drag head. A larger number of penetration bodies results in a lower average penetration depth inside the bottom. Surprisingly, the expected lower performance in this way is fully compensated by the application of the individually mobile pressure elements.

In a preferred embodiment the drag head according to the invention is characterized in that the pressure elements are received on the visor by means of guiding means, this in such a way that the pressure elements can be moved in a direction substantially perpendicular to the background. Such a variant has the advantage that the full weight of each pressure element is used substantially. This is so because in this variant embodiment each pressure element can move substantially "freely" (apart from frictional forces and the like) in a direction perpendicular to the bottom.

Still another preferred embodiment refers to a drag head provided with disk-shaped penetrating bodies which transmit forces to the bottom through its peripheral edge under the influence of the weight of the pressure element in which they are received. Since the disk-shaped penetration bodies are preferably disposed with their disk plane substantially perpendicular to the lower surface of the pressure elements and also partially protrude from this lower surface, their peripheral edge comes into contact with the bottom surface. The weight of the pressure element under the associated water of the pitcher dredge is thus distributed over the contact surface between the penetration body and the bottom surface. A high pressure develops locally in this way which effectively crushes the bottom and in particular a relatively hard bottom.

It is advantageous to characterize the drag head according to the invention because the penetration bodies extend in a line and substantially transversely to the dredging direction. Placing particularly the disk-shaped penetration bodies in a line, it has been found, surprisingly, that not only the bottom is crushed under the penetration bodies, but also those parts of the bottom located between the penetration bodies.

The number of disk-shaped penetration bodies per pressure element can be chosen within wide limits. The number of disc-shaped penetration bodies per pressure element is preferably between 2 and 20, more preferably between 2 and 10 and most preferably between 3 and 5. A particularly suitable intermediate distance in the transverse direction between two penetration bodies successive it is between 5 and 50 cm, more preferably between 8 and 35 cm and most preferably between 10 and 20 cm. The number of pressure elements in the drag head according to the invention can also be varied within wide limits. A large number of pressure elements has the advantage that the bottom contour can be followed more precisely, although the average force transmitted to the bottom by the penetration bodies decreases. A small number of pressure elements results in a simpler construction. A good compromise is obtained when the number of pressure elements is between 2 and 20, more preferably between 2 and 8 and most preferably between 3 and 5.

The drag head is dragged on the bottom below the water, where according to the invention it mainly makes contact with the bottom by means of the penetration bodies, in particular the disk-shaped penetration bodies. Therefore, it is advantageous to characterize the drag head because the disk-shaped penetration bodies are received in the pressure elements for rotation around its axis, the axis perpendicular to the plane of the disk, where the axis of rotation is substantially at a right angle to the drag direction. In this way it is achieved that considerably less power is required to move the pitcher dredge with suction tube at normal speeds.

An additional advantage of the drag head according to the invention is that the bottom can be crushed into relatively small soil particles, whereby the latter are suctioned in good performance. This is understood to mean that the concentration of relevant particles in the water sucked up is relatively high.

In order to protect the disk-shaped penetration bodies, the pressure elements of the drag head are preferably provided with a series of teeth that extend substantially transversely to the direction of drag and that engage in the bottom upstream of the disk-shaped penetration bodies during use. The teeth break a certain part of the ground before the penetrating bodies reach this part of the ground. The teeth can also level the bottom, so the disk-shaped penetration bodies can do their job more effectively. The combination of teeth and disc-shaped penetration bodies also provides increased performance.

An additional improved drag head is obtained when the pressure elements are also provided with support means which, during use, are engaged in the bottom upstream of the disk-shaped penetration bodies and optionally of the teeth. In the case of a great irregularity in the bottom these support means ensure that the pressure elements, and possibly even the entire visor, are forced to follow the contour of the bottom. This prevents jamming or damage of the drag head and in particular of the disk-shaped penetration bodies. In a particularly suitable embodiment, the support means comprise a series of sliding blocks preferably arranged in the transverse direction. The sliding blocks are profiled in such a way that the drag head does not tend to dig itself but, on the contrary, tends to follow the contour of the bottom. The sliding blocks thus also have a protective function.

The disk-shaped elements will generally submerge a certain depth of penetration inside the bottom under the weight of the pressure elements. This typical penetration depth can be determined during the design of the disk-shaped penetration bodies. In an advantageous embodiment variant, the drive head according to the invention is characterized in that the teeth are preferably engaged at the bottom from 1/2 to 10 times, more preferably from 1/2 to 5 times and most preferably 1/2 at 1/2 times the penetration depth of the disk-shaped penetration bodies higher than the disk-shaped penetration bodies. The teeth thus have an optimal protective effect and the highest yield is obtained. The teeth also have a depth of penetration. The depth of penetration of the teeth is preferably limited in order to avoid breaking the teeth or excessively high cutting forces. It is advantageous in this case that the lower side of the support means is placed at a predetermined distance, preferably limited, above the lower side of the teeth. The support means are preferably positioned in such a way that they fit at the bottom higher than the teeth, more preferably 1/2 to 1/2 times the depth of penetration of the teeth. An even better protective effect is obtained due to this measure, as well as additional improved performance.

In a further improved preferred embodiment, the drive head according to the invention is provided with closing means for at least partially closing the opening between the components and in particular between the visor and the bottom. The provision of closing means ensures that the suction force supplied through the suction pipe is as would be the suction of the drag head on the bottom. The developed suction force ensures a sufficient pressure tension below the bottom penetration bodies, so that the bottom is broken, crumbled or otherwise crushed. The closing of the opening between the visor and the bottom can be done in any way known to an expert person. The closing means can therefore comprise a tape of flexible material, this tape extending over the opening and being fixed to the relevant component on at least one side of the opening.

With respect to the dimensions of the penetration bodies it can be seen that they are chosen subject to, among other factors, the intended pressure forces and the number of penetration bodies per pressure element. The diameter of the penetration bodies can vary from several centimeters to a series of decimeters. Particularly suitable diameters are between 2 and 80 cm, more preferably between 5 and 60 cm and most preferably between 10 and 40 cm. Penetration bodies with diameters of this type have a good balance between the power required per meter of advance and the dredging performance to be achieved, this is the number of m3 of ground dredged per second.

If desired, the drag head according to the invention may be provided with at least one series of water jet pipes, preferably under pressure. Normal pressures for example are around 10 to 200 bar, although pressures of 2500 bar are also possible. Water jets can be directed to the bottom in front of, or above or behind the penetration bodies in order to improve dredging performance.

The invention also relates to a method according to claim 16, for breaking or dredging at least partially a hard bottom under water with a pitcher dredge with suction tube, equipped with a drag head according to the invention. The method comprises lowering a drag head according to the invention on the bottom, after which it is dragged on the bottom. A suction force is exerted therein through the suction pipe in the space at least partially closed through the closing means and enclosed by the visor and the bottom, so that the penetration bodies in the form of disc penetrate through its peripheral edge inside the bottom and cause cracks in it under the influence of the weight of the pressure elements and the suction force. Shavings released from broken ground are sucked up through the suction pipe.

According to the invention the pressure elements in that place move independently of each other, whereby improved performance is achieved. During dredging the pressure elements preferably move independently of one another in a direction substantially perpendicular to the bottom. In a preferred method, the support means of a pressure element are first coupled to the bottom, where the pressure element is forced to follow the contour of the bottom, after which the teeth are then coupled to the bottom so that the bottom is leveled at least partially, after which the penetration bodies engage in the bottom.

The drag head and the method according to the invention will now be further clarified on the basis of the following description of preferred embodiments and the figures, without limiting the invention thereto. In the figures:

Figure 1 shows a schematic perspective view from below of a drag head according to the invention;

Figure 2 shows a schematic perspective view from above of the drag head of Figure 1;

Figure 3 shows a schematic perspective view from below of a pressure element of the drag head according to the invention;

Figure 4 shows a schematic perspective view from above of a construction of a support in which the pressure elements can be received, as shown in Figure 3; and finally

Figure 5 shows a schematic view of a drag head according to the invention in operation.

A drag head 1 for a pitcher dredge with suction tube is shown with reference to figure 1. The drag head 1 comprises a visor 2 which during use is dragged on the bottom 50 in the direction of drag P ( see also figure 5) and in that place loosen the ground, and a suction pipe 3 which is connected to the visor 2 and unloads the loosened ground. The visor 2 is provided with side walls (84, 85) and an upper plate 86 which is connected to the suction pipe 3. In the represented embodiment of the drag head according to the invention the visor 2 comprises four pressure elements individually movable (21, 22, 23, 24) transversely to the drag direction P. The pressure elements (21, 22, 23, 24) are received in the visor 2 by means of guide means (211, 212, 213 , 214, 215, 216, 217, 218) (see Figure 3). The visor 2 comprises for this purpose a support structure, represented in Figure 4, which in the variant of embodiment represented comprises four chambers (25, 26, 27, 28) in which the pressure elements are received ( 21, 22, 23, 24). The guide means comprise 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, 218) arranged on the front wall 32, which can roll on the corresponding rear wall 41 and front wall 42 of the chambers (25, 26, 27, 28). In order to prevent the pressure elements (21, 22, 23, 24) from escaping from the visor 2, each pressure element is provided with abutment edges (33, 34) respectively on the rear wall 31 and the wall front 32. The pressure elements (21, 22, 23, 24) can thus be moved relatively freely in a direction L, which runs substantially perpendicularly to the bottom 50, in which the abutment edges (33, 34) rest at the upper edge of the chamber 25 in the lowest position of, for example, the pressure element 21.

As shown in Figure 3 for the pressure element 21, each pressure element (21, 22, 23, 24) is provided with four penetration bodies (51, 52, 53, 54). The penetration bodies (51, 52, 53, 54) are disk-shaped and transmit forces to the bottom 50 through their peripheral edge under the influence of the weight of the pressure element in which they are received, thereby causing cracks in the background. In each pressure element the disk-shaped penetration body (51, 52, 53, 54) extends in a line that runs substantially transversely to the drag direction P. The penetration bodies of all the pressure elements are preferably arranged in such a way that together they also extend in a line that runs substantially transversely to the drag direction P. This configuration is shown in Figure 1.

In the embodiment shown, the pressure elements (21, 22, 23, 24) of the drive head 1 are also provided with a series of teeth (61, 62, 63, 64) which extend substantially transversely to the direction of drag P and which are coupled at the bottom 50 upstream of the disk-shaped penetration bodies (51, 52, 53, 54) during use. The pressure elements (21, 22, 23, 24) are additionally provided with support means (71, 72, 73, 74). These comprise sliding blocks, for example of steel, with a lower surface which runs obliquely from the front wall 32 of a relevant pressure element 21 to the disk-shaped penetrating bodies (51, 52, 53, 54) or the teeth (61, 62, 63, 64). During use the support means (71, 72, 73, 74) are engaged in the bottom upstream of the disk-shaped penetration bodies (51, 52, 53, 54) and optionally the teeth (61, 62, 63, 64), so that they are the first to engage the bottom 50. The associated pressure element is therefore forced to follow the contour of the bottom 50. In the case of a lift at the bottom 50 the relevant pressure element it will be pushed up and even before the teeth (61, 62, 63, 64) and that the penetration bodies (51, 52, 53, 54) can penetrate the bottom. The support means (71, 72, 73, 74) not only provide protection for teeth and disc-shaped penetration bodies, but also control the desired penetration depth of the penetration bodies (51, 52, 53 , 54, 61, 62, 63, 64). Since the teeth (61, 62, 63, 64) are engaged in the bottom upstream of the disk-shaped penetration bodies (51, 52, 53, 54), the teeth of similar shape provide protection for the bodies of disk-shaped penetration and also control the desired penetration depth of the penetration bodies (51, 52, 53, 54). The best results are obtained when the lower side of the support means is placed at a predetermined distance, preferably limited, above the lower side of the teeth. This is, for example, the case when the teeth (61, 62, 63, 64) have a depth of penetration and the support means are engaged at the bottom of 50 1/2 to 1 1/2 times the depth of penetration of the teeth. teeth higher than the teeth and when the disc-shaped penetration bodies (51, 52, 53, 54) have a depth of penetration and the teeth (61, 62, 63, 64) are coupled at the bottom of 50 1 / 2 up to 1 1/2 times the penetration depth of the disk-shaped penetration bodies higher than the disk-shaped penetration bodies.

In the embodiment of the drag head 1 represented for example in Figure 1, the visor 2 is provided with closing means which substantially close the opening between the visor 2 and the bottom 50 in order to avoid the possibility that the Water supplied is supplied along the relatively unproductive sides of the visor 2. The closing means comprise closing plates (81, 82) which are arranged on both side walls (84, 85) and which are sliding in height and, if desired, they are provided at the bottom edges thereof with a rubber cover layer. On the lower upstream side, the visor 2 is provided with at least one foundation plate 83 which provides sufficient support at the bottom 50 and prevents water from being sucked along the upstream side.

During dredging a sub-pressure is maintained inside the drag head 1 to allow loose particles of hard ground and other soil particles to be sucked through the suction pipe

3. With reference to Figure 5, the method according to the invention comprises lowering the drag head 1 to the bottom 50 and the drag of the drag head 1 onto the bottom 50 in a drag direction P. A suction force is exerted on that place by means of the suction pipe 3 in the space at least partially closed through the closing means (84, 85) and enclosed by the visor 2 and the bottom 50 so that the disk-shaped penetration bodies ( 51, 52, 53, 54) penetrate through its peripheral edge inside the bottom 50 and cause cracks therein under the influence of the weight of the pressure element in which they are received. Applying a large number of disk-shaped penetration bodies (51, 52, 53, 54) placed adjacent to each other, it has been found that the bottom between the penetration bodies is also crushed, so that the yield is considerable . The chips removed from the broken bottom are sucked upwardly through the suction pipe 3. According to the invention the pressure elements (21, 22, 23, 24) are here substantially independently transferred from one another in a substantially L direction perpendicular to the bottom 50. A large number of penetration bodies by this means remains in contact with the bottom 50, whereby an increased yield is achieved in relation to the prior art despite the possible smaller average penetration depth. The support means (71, 72, 73, 74) are first coupled to the bottom 50 and provide, among other things, protection to the penetration bodies. Additional improved performance is achieved by applying a combination of disc-shaped teeth and penetration bodies, where the teeth are the first to engage at the bottom at a given depth of penetration so that the bottom 50 is leveled by at least partially, after which the disk-shaped penetration bodies engage in the bottom

50. It may also be advantageous to provide a drag head in which the disk-shaped penetration bodies are first coupled to the bottom at a certain depth of penetration so that the bottom 50 is broken at least partially, after which teeth are then coupled at the bottom 50.

The invention is not limited to the exemplary embodiments described hereinbefore and modifications may be made thereto to the extent that they fall within the scope of the appended claims.

Claims (16)

one.

Drag head (1) of a pitcher dredge with suction tube comprising a visor (2) which is dragged on the bottom (50) and in that place loosen the ground and a suction pipe (3) which is connected to the visor (2) and which discharges the loosened terrain characterized in that the visor (2) comprises at least two individually movable pressure elements (21, 22, 23, 24) transversely to the drag direction, in which A pressure element is provided with a series of penetration bodies (51, 52, 53, 54, 61, 62, 63, 64) which transmit forces to the bottom (50) under the influence of the weight of the pressure element.

2.

Drag head as claimed in claim 1 characterized in that the pressure elements (21, 22, 23, 24) are received in the visor (2) by means of guide means (211, 212, 213, 214), this such that the pressure elements (21, 22, 23, 24) can be moved in a direction substantially perpendicular to the bottom (50).

3.

Drag head as claimed in claim 1 or 2, characterized in that the penetration bodies comprise disk-shaped penetration bodies (51, 52, 53, 54) which transmit forces to the bottom (50) through their peripheral edge (23) under the influence of the pressure element weight.

Four.

Drag head as claimed in claim 3 characterized in that the disk-shaped penetration bodies (51, 52, 53, 54) extend in a line and substantially transversely to the direction of dredging.

5.

Drag head as claimed in any of the preceding claims characterized in that the number of disk-shaped penetration bodies (51, 52, 53, 54) per pressure element is between 2 and 10 and more preferably between 3 and 5.

6.

Drag head as claimed in any of the preceding claims characterized in that the number of pressure elements (21, 22, 23, 24) is between 2 and 8 and more preferably between 3 and 5.

7.

Drag head as claimed in any of the preceding claims characterized in that the pressure elements (21, 22, 23, 24) are provided with a series of teeth (61, 62, 63, 64) that extend substantially transversely to the direction of drag and that are coupled at the bottom (50) upstream of the disk-shaped penetration bodies during use (51, 52, 53, 54).

8.

Drag head as claimed in any of the preceding claims characterized in that the pressure elements (21, 22, 23, 24) are provided with support means (71, 72, 73, 74) which, during use, are coupled in the bottom (50) upstream of the disc-shaped penetration bodies (51, 52, 53, 54) and optionally of the teeth (61, 62, 63, 64).

9.

Drag head as claimed in claim 8, characterized in that the support means (71, 72, 73, 74) comprise sliding blocks.

10.

Drag head as claimed in any one of claims 7-9 characterized in that the disk-shaped penetration elements (51, 52, 53, 54) have a depth of penetration and because the teeth (61, 62, 63, 64 ) are fitted at the bottom higher than the disk-shaped penetration bodies.

eleven.

Drag head as claimed in any of claims 8-10 characterized in that the teeth (61, 62, 63, 64) have a depth of penetration and because the support means (71, 72, 73, 74) are coupled in the bottom (50) taller than the teeth.

12.

Drag head as claimed in any one of the preceding claims characterized in that the drag head (1) is provided with closing means (81, 82) which substantially close the opening between the visor (2) and the bottom (50) .

13.

Drag head as claimed in any of the preceding claims characterized in that the drag head comprises at least one series of jet pipes for water injection under high pressure.

14.

Procedure for dredging in a bottom at least partially hard below the water with a pitcher dredger with suction tube equipped with a drag head (1) as claimed in any one of claims 1-13, wherein the drag head is lowered on the bottom (50) and dragged thereon, in which a suction force is exerted through the suction pipe (3) in the space at least partially closed through closing means and enclosed by the visor (2) and the bottom, so that the disk-shaped penetration bodies (51-54) penetrate through its peripheral edge inside the bottom and cause cracks therein under the influence of the weight of the pressure and underpressure elements and in which the chips removed from the broken ground are sucked upwards through the suction pipe (3).

fifteen.

Method as claimed in claim 14, characterized in that during dredging the pressure elements (21-24) move independently of each other in a direction substantially perpendicular to the bottom (50).

16. The method as claimed in claim 14 or 15, characterized in that the support means (71-74) of a pressure element (21-24) are first coupled to the bottom, wherein the pressure element is forced to follow the bottom contour, in which the teeth (61-64) are then engaged in the bottom so that the bottom is leveled at least partially, after which the penetrating bodies engage in the bottom.