Suction dredger with dredging tube of variable length

Abstract

 A suction dredger comprises a dredging tube (3) which at one end is connected to a suction head (4) and which at the other end is connected to the suction dredger hull (1) by means of a pivot connection (7) having a pivot axis which is horizontally and transversely oriented with respect to said hull (1), and a suspension device (13, 14) by means of which said dredging tube (3) is displaceable between a generally horizontal rest position and an inclined dredging position, said dredging tube (3) comprising a frame (21) and a tube device (20) supported by said frame (21). The dredging tube (3) has a variable length.

Description

[0001] The invention is related to a suction dredger comprising a dredging tube which at one end is connected to a suction head and which at the other end is connected to the suction dredger hull by means of a pivot connection having a pivot axis which is horizontally and transversely oriented with respect to said hull, and a suspension device by means of which said dredging tube is displaceable between a generally horizontal rest position and an inclined dredging position, said dredging tube comprising a frame and a tube device supported by said frame.

[0002] A suction dredger of this type is disclosed in GB-A-657.289. The dredging tube of said prior art suction dredger comprises several sections, which provide a specific length. Depending on the length of the dredging tube, a specific dredging depth can be obtained taking into account the maximum inclination of the dredging tube. Having regard to the circumstance that the dredging tube in the rest position has to be supported along the hull, it preferably should not protrude with respect to the stem or bow of the suction dredger hull. Therefore, the maximum length of the dredging tube, and thus the maximum dredging depth which is attainable by means of this dredging tube, is limited.

[0003] The object of the invention is to provide a suction dredger of the type described before which allows for a relatively long dredging tube, and therefore a relatively large dredging depth. This object is achieved in that the dredging tube has a variable length. Thus, in the dredging position, the dredging tube can be extended to a maximum length, which means that the dredging operation can be carried out at a relatively large depth. On the other hand, in the rest position the dredging tube can be brought in a minimum position for storage without protruding with respect to the suction dredger hull.

[0004] Preferably, the tube device is provided with tube device parts which are displaceable with respect to each other in the longitudinal direction of the dredging tube. With the aim of providing a reliable construction, which is able to withstand relatively hard bottom material parts which are sucked through the tube device, the tube device parts can be of a rigid nature and can be telescopically accommodated within each other. Preferably, the inner tube device part has a outwardly extending flange and the outer tube device part has an inwardly extending flange, said flanges abutting each other in the extended position of the tube device.

[0005] In such layout, the rest position length and dredging position length of the dredging tube are well defined. Furthermore, the facing surfaces of the flanges may comprise sealing means. Thus, in the dredging position the tube device parts are properly sealed with respect to each other so as to maintain the required pressure within the dredging tube.

[0006] As described before, the tube device parts are carried out in such a way that they are telescopic. In this connection, also the frame is provided with frame parts which are displaceable with respect to each other in the longitudinal direction of the dredging tube. Preferably, each frame part comprises longitudinally extending beams, in such a way that a beam of one frame part and a beam of the other frame part are supported with respect to each other by means of roller/roller track systems. These roller/roller track systems provide a low friction, and therefore less resistance, between the frame parts upon displacing these with respect to each other. Also, less wear and better stability are obtained.

[0007] Generally speaking, it is desirable to obtain an elongation of the dredging tube which is as large as possible on the one hand, while maintaining the desired stability both in the extended and in the retracted position on the other hand. This means that a certain overlap between the frame parts should be maintained, also in the extended position. A good compromise between these two conditions can be struck in the embodiment according to which each beam carries rollers at one of its ends and a roller track at its opposite end, the beams being arranged in pairs in such a way that the roller tracks of one beam of a pair contact the rollers of the other beam of said pair.

[0008] The roller axes are oriented transversely with respect to the longitudinal direction of the dredging tube. Preferably, the roller tracks are provided on I-profiles or T-profiles. At least one roller contacts a flange of a profile, and at least two rollers contact the opposite sides of the web of the profile. Preferably, two rollers are in contact with the flange of the profile, one roller on each side of the web of the profile. Furthermore, the beams of one frame part are positioned within the beam of the other frame part. In this connection, preferably the inner beam comprises an essentially flat strip and the outer beam comprises a generally U-shaped profile, the legs of said U-shaped profile facing the essentially flat strip. For the purpose of limiting the amount of the displacement of the frame parts with respect to each other, and for maintaining the required stability of the suction tube in the extended condition, each pair which consists of a beam of one frame part and a beam of the other frame part may comprise abutment means which define the extended position of the dredging tube. Similarly, each pair which consists of a beam of one frame part and a beam of the other frame part may comprise abutment means which define the retracted position of the dredging tube. According to a preferred embodiment, each frame part comprises at least three longitudinal longitudinally extending beams. A very stable embodiment with a limited weight is obtained in case the beams of the inner frame part are interconnected through a truss construction. Similarly, the beams of the outer frame part may be interconnected through a truss construction.

[0009] Preferably, the dredging tube comprises at least two pivotably connected dredging tube device parts, the upper dredging tube part or end part of which dredging tube being connected to the suction dredger hull, and at least one of the other dredging tube parts having a variable length. Also, the dredging tube comprises at least two pivotably connected dredging tube parts, are of said dredging tube parts carrying a suction pump, and at least one other dredging tube part having a variable length. The invention will now be described further with reference to an embodiment of the dredging tube as shown in the drawings.

Figure 1 shows a side view of a suction dredger having a dredging tube according to the invention.

Figure 2 shows a view in perspective of the partially extended dredging tube according to the invention.

Figures 3a and 3b show the fixed part of the dredging tube according to figure 2.

Figure 4 shows the movable part of the dredging tube according to figure 2.

Figure 5 shows a further detail of the fixed part of the dredging tube according to figure 3.

Figure 6 shows a detail of the tube parts.

[0010] The suction dredger shown in figure 1 comprises a suction dredger having a hull 1 onto a side wall of which a dredging tube is connected which has been indicated in general by 3. The dredging tube 3 is shown in full lines in its operating position, that is with the suction head 4 lowered onto the bottom 16 of the body of water 17. The dredging tube 3 is supported by means of hoisting devices 14 having cables 13 for transferring the dredging tube 3 between its operating position as shown in figure 1 in full lines, and its generally horizontal rest position, shown in dotted lines, alongside the suction dredger hull 1. In this connection, the dredging tube has an elbow 5 which is connected to an aperture in the suction dredger hull 1 in such a way that the dredging tube 3 is rotatable around a pivot axis 7 which extends transverse with respect to said side wall. By means of the propulsion unit 29, the suction dredger and thus the suction head is manoeuvred with respect to the bottom 16 as desired.

[0011] In the embodiment shown, the dredging tube 3 consists of an upper part 8 and a lower part 6. These parts are interconnected through the pivot joint 11. Furthermore, the upper part 8 is connected to the elbow 5 through a pivot joint 10 which is transverse with respect to the pivot axis 7 of the elbow 5. The upper part is equipped with a suction pump 9. By means of suitable tubing 12, the mixture of water and bottom material loosened by the suction head 4 and pumped by the suction pump 9 is fed into the hopper 15 of the suction dredger.

[0012] As will be clear from the two positions shown in figure 1, the operating depth of the suction dredger is determined to a large extent by the total length of the dredging tube 3, in other words by the distance between the elbow 7 and the suction head 4. This is caused by the fact that in the horizontal rest position the dredging tube 3 should not protrude with respect to the heck of the suction dredger hull 1. Having regard to the fact that the angle of the dredging tube 3 with respect to the horizontal in the operating position is limited, a larger dredging depth can only be obtained by using a longer dredging tube. However, as explained before, the length of the dredging tube is more or less dictated by the length of the suction dredger hull.

[0013] In the case of the suction dredger as shown in figure 1 however, a larger dredging depth can nevertheless be obtained as a result of the possibility to extend the lower part 6 of the dredging tube 3. This is highlighted by the difference in the level of the bottom as shown in dotted lines, which can be treated by means of a traditional dredging tube, and of the bottom as shown in full lines, which can be treated by means of the extended dredging tube 3 according to the invention. The difference in the level of these working depths is indicated by the letter H.

[0014] The lower part 6 of the dredging tube 3 has been shown on a larger scale in figure 2. The said lower part 6 has been shown in a somewhat extended position, and has a variable length which is obtained by displacing its two telescopic parts 18, 19 with respect to each other. In the embodiment shown, the fixed telescopic part 19 of the lower part 6 is connected to the elbow 5, and the displaceable telescopic part 18 can be displaced into and out of the fixed telescopic part 19. The lower part 6 of the dredging tube 3 comprises a tube device which has been indicated by reference 20, as well as a frame 21 which supports the tube device 20. Said tube device 20 consists of the fixed tube device part 22, which forms part of the fixed dredging tube part 19, and a telescopic tube device part 23 which forms part of the displaceable tube device telescopic part18. In the embodiment shown, the telescopic tube device part 23 is accommodated within the fixed tube device part 22, although a reverse embodiment is possible as well.

[0015] The frame 21 comprises a fixed frame part 24 which forms part of the fixed telescopic part 19, and a telescopic frame part 25 which forms part of the displaceable telescopic part 18. In the embodiment shown, the telescopic frame part 25 is accommodated within the fixed frame part 24, although a reverse embodiment is possible as well. A pressure conduit 26 forms part of the lower part of the dredging tube 8 as well. Said pressure conduit 26 comprises a fixed pressure conduit part 27, which forms part of the fixed frame part 19, and the telescopic pressure conduit part 28, which forms part of the telescopic frame part 18. In the embodiment shown, the telescopic pressure conduit part 28 is accommodated within the fixed pressure conduit part 27, although the reverse embodiment is possible as well.

[0016] The fixed dredging tube part 19 carries a drive means 29 for displacing the telescopic dredging tube part 18. Said drive means 29 comprises hydromotors 30 (other motors are possible as well), connected to a dual drive drum 31. And a distance from the dual drive drum, an auxiliary dual drum 32 is connected to the fixed telescopic part 19. A cable without end 33 has been wound around the dual drums 31, 32. A slide 34 is connected to the cable 33, which slide 34 extends through a longitudinal slit 35 in the fixed to the frame part 24, and is connected to the telescopic frame part 25. By energising the hydromotors 30, the cable 33 and thus the slide 34 is driven back and forth for displacing the displaceable telescopic part 18 with respect to the fixed telescopic part 19.

[0017] Figures 3a and 3b show the fixed telescopic part 19 in isolation. It is shown that said fixed telescopic part 19 comprises a fixed frame part 24 which consists of in total three U-beams 36 which are interconnected through the truss constructions 37. At the upper end of the dredging tube or 19, a baffle plate 38 is provided onto which the beams 36 are connected. Said beams 36 comprise flanges 39, positioned on both sides of the base 40. As shown in figure 5, an I-profile 40 is provided at one end, that is the upper end, of each beam 36. Said I-profile 40 comprises a web 41 and a free flange 42 extending on both sides of the web 41. At the opposite end of the beam 36, rollers 43 are provided which are rotatable about roller axes which are parallel to the base 40 and which are perpendicular with respect to the flanges 39. These rollers are to bear on a similar I-profile of the telescopic dredging tube part 18 as will be described below with reference to figure 4. Furthermore, rollers 44 are provided which are rotatable about roller axes parallel to the flanges 39 of the U-beams 36 and perpendicular with respect to the base 40 of said U-beams 36.

[0018] Figure 4 shows the telescopic dredging tube part 18 which consists of in total three strips like beams 46, interconnected through truss constructions 47. The lower end of the telescopic dredging tube part 18 is connected to the baffle 48. Adjoining said baffle plate 48, each strip 46 carries an I-beam 45, having a web 49 and a free flange 50 extending on both sides of the web 49. At the opposite end, each strip 46 comprises rollers 52 the rotation axis of which are parallel to the strips 46 and transverse with respect to the longitudinal direction of the telescopic dredging tube part 18, as well as rollers 53 the rotation axis of which is perpendicular with respect to the strip 46.

[0019] Now turning to the fixed dredging tube part 19, the I-profile 40 thereof is in cooperation with the rollers 52, 53 of the telescopic dredging tube part 18, supported by roller plates 57. In particular, the rollers 52 are in contact with the inner side of the flange 42 of the I-profile 40, and the rollers 53 contact opposite sides of the web 41 thereof. Conversely, the I-profile 45 of the telescopic dredging tube part 18 is in cooperation with the rollers 43, 44 of the fixed dredging tube part 19. In particular, the rollers 43 are in contact with the inner side of the flange 50 of the I-profile 45, and the rollers 44 are in contact with opposite sides of the web 49 of the I-profile 45. Thus, a firm and a reliable support of the dredging tube parts 18, 19 with respect to each other is obtained.

[0020] In the extended position of the lower part 6, the tube parts 22, 23 can be sealed with respect to each which other so as to maintain the suction flow through the tube device 20. In this connection, the (inner) telescopic tube part 23 has an outwardly extending flange 54, and the (outer) fixed tube part 22 has an inwardly extending flange 55. Between these the flanges and 54, 55, the sealing 56 is present in such a way that, after the flanges 54, 55 abut to each other, the tube device 22 is sealed properly.

[0021] The beams 36 of the fixed dredging tube part 19 comprises abutment means 51 (see figure 5) which determine the extended position of the dredging tube 3. In the extended position, the roller plates 57 abut the abutment means 51.

List of references

[0022] 

1

suction dredger hull

2

side wall

3

dredging tube

4

suction head

5

elbow

6

dredging tube lower part

7

pivot - axis

8

dredging tube upper part

9

suction pump

10

pivot joint

11

pivot joint

12

tubing

13

cable

14

hoisting device

15

hopper

16

bottom of 17

17

body of water

18

displaceable telescopic part of dredging tube 3

19

fixed telescopic part of dredging tube 3

20

tube device of 6

21

frame of 6

22

fixed tube device part of 19

23

telescopic tube device part of 18

24

fixed frame part of 18

25

propulsion unit 6

26

pressure conduit of 6

27

fixed pressure conduit part of 19

28

telescopic pressure conduit part of 18

29

drive means

30

hydro motors

31

dual drive drum

32

auxiliary dual drum

33

cable without end

34

slide

35

slit in 24

36

U-beam of 19

37

truss construction of 19

38

baffle plate of 19

39

flange of 36

40

I-profile of 19

41

web of 19

42

flange of 19

43

roller of 19

44

roller of 19

45

I-beam of 18

46

strip like beam of 18

47

truss construction of 18

48

baffle of 18

49

web of 18

50

flange of 18

51

abutment

52

roller of 18

53

roller of 18

54

flange of 18

55

flange of 19

56

sealing

57

roller plate

Claims

1. Suction dredger, comprising a dredging tube (3) which at one end is connected to a suction head (4) and which at the other end is connected to the suction dredger hull (1) by means of a pivot connection (7) having a pivot axis which is horizontally and transversely oriented with respect to said hull (1), and a suspension device (13, 14) by means of which said dredging tube (3) is displaceable between a generally horizontal rest position and an inclined dredging position, said dredging tube (3) comprising a frame (21) and a tube device (20) supported by said frame (21), characterised in that the dredging tube (3) has a variable length.

2. Suction dredger according to claim 1, wherein the tube device (20) is provided with tube device parts (22, 23) which are displaceable with respect to each other in the longitudinal direction of the dredging tube (3).

3. Suction dredger according to claim 2, wherein the tube device parts (22, 23) are of a rigid nature and are telescopically accommodated within each other.

4. Suction dredger according to claim 3, wherein the inner tube device part (23) has an outwardly extending flange (54) and the outer tube device part (22) has an inwardly extending flange (55), said flanges (54, 55) abutting each other in the extended position of the tube device.

5. Suction dredger according to claim 4, wherein the facing surfaces of the flanges (54, 55) comprise sealing means (56).

6. Suction dredger according to any of the preceding claims, wherein the frame (21) is provided with frame parts (24, 25) which are displaceable with respect to each other in the longitudinal direction of the dredging tube (3).

7. Suction dredger according to claim 6, wherein each frame part (24, 25) comprises longitudinally extending beams (36, 46), a beam of one frame part and a beam of the other frame part each time being supported with respect to each other by means of roller/roller track systems (43, 44, 45; 52, 53, 40).

8. Suction dredger according to claim 7, wherein each beam (36, 46) carries rollers (43, 44; 52, 53) at one of its ends and a roller track (45, 40) at its opposite end, the beams being arranged in pairs in such a way that the roller tracks of one beam of a pair being contact with the rollers of the other beam of said pair.

9. Suction dredger according to claim 8, wherein the roller axes are oriented transversely with respect to the longitudinal direction of the dredging tube.

10. Suction dredgers according to claim 8 or 9, wherein the roller tracks are provided on I-profiles (45; 40) or T-profiles.

11. Suction dredger according to claim 10, wherein at least one roller (43, 52) contacts a flange (50, 42) of a profile (45, 40), and at least two rollers (53, 44) contact the opposite sides of the web (49) of the profile (45, 40).

12. Suction dredger according to any of claims 7-11, wherein one beam of a frame part is positioned within one beam of the other frame part.

13. Suction dredger according to claim 12, wherein the inner beam comprises an essentially flat strip (46) and the outer beam comprises a generally U-shaped profile (36), the legs (39) of said U-shaped profile (36) facing the essentially flat strip (46).

14. Suction dredger according to any of claims 7-13, wherein each pair of a beam of one frame part and a beam of the other frame part comprises abutment means (57) which define the extended position of the dredging tube (3).

15. Suction dredgers according to any of claims 7-14, wherein each pair of a beam of one frame part and a beam of the other frame part comprises abutment means (51, 57) which define the retracted position of the dredging tube.

16. Suction dredger according to any of claims 6-15, wherein drive means (29) are provided for displacing the frame parts with respect to each other.

17. Suction dredger according to any of the preceding claims, wherein each frame part (24, 25) comprises at least three longitudinal longitudinally extending beams (36, 46).

18. Suction dredger according to claim 17, wherein the beams (46) of the inner frame part (25) are interconnected through a truss construction (47).

19. Suction dredger according to claim 17 or 18, wherein the beams (36) of the outer frame part (24) are interconnected through a truss construction (37).

20. Suction dredger according to any of the preceding claims, within the dredging tube (3) is provided with a pressure conduct (26) having a variable length.

21. Suction dredger according to claim 20, wherein the dredging tube (3) comprises telescopically arranged pressure conduit parts (27, 28).

22. Suction dredger according to any of the preceding claims, wherein the dredging tube (3) comprises at least two pivotably connected dredging tube device parts (6, 8), the upper dredging tube part (c) or end part of which dredging tube (j) being connected to the suction dredger hull (1), and at least one of the other dredging tube parts (6) having a variable length.

23. Suction dredger according to any of the preceding claims, wherein the dredging tube (1) comprises at least two pivotably connected dredging tube parts (6, 8), are of said dredging tube parts (8) carrying a suction pump (60), and at least one other dredging tube part (6) having a variable length.

Drawing