WO2015119496A1

WO2015119496A1 - Extended suction tube for a hopper dredger

Info

Publication number: WO2015119496A1
Application number: PCT/NL2015/050069
Authority: WO
Inventors: Erwin Put; Dirk Cornelis STANDER; Theodorus Adrianus Koning
Original assignee: Ihc Holland Ie B.V.
Priority date: 2014-02-05
Filing date: 2015-02-03
Publication date: 2015-08-13
Also published as: NL2012205C2

Abstract

An extended suction tube for a vessel includes a first portion (16) which extends along the vessel in a length direction when not in use, a second portion (18) which extends along the vessel in a width direction when not in use, and a third portion (20) which extends along the vessel in a length direction when not in use. The first portion pivotally connects to the vessel when in use, and the second portion pivotally connects to the first portion on a first end and to the third portion on a second end.

Description

EXTENDED SUCTION TUBE FOR A HOPPER DREDGER

Trailing suction hopper dredgers ("TSHD") are vessels which can be used to dredge at sea or in open water. TSHD's typically use a suction tube, one end of which can be lowered to the seabed and used to suck up solids such as sand, sludge or sediment, mixed with water. The lower end of this suction tube can be provided with a suction head or a draghead. The solid material mixed with water is pumped through the suction tube into a hopper of the dredging vessel.

The suction tube is typically pivotably connected to the vessel so that it can extend beneath the water to the seabed. A rigid suction tube allows for steerability in relation to the vessel. When not in use, a rigid suction tube is typically stored on the vessel, extending the length of the vessel on one side. Thus, the length of the suction tube is limited by the length of the vessel. For example, EP1039041 discloses a rigid suction tube which is made of two or three sections coupled by hinge connections. The hinged connections allow the draghead to maintain contact with the waterbed bottom and maintain the same speed despite different water conditions. However, the length of the suction tube in EP1039041 is still limited by the length of the vessel and is only slightly longer than a suction tube without coupled sections. JP H0671548 also discloses a system with a plurality of pipes connected by joints which allow picoting and rotation. EP2034096 also discloses a vessel with a dredging tube extending from each side. The suction tube of EP2034096 is made of a frame carrying an upper tube section and two lower tube sections connected by pivots.

Some past rigid suction tubes have been made of telescopic parts, which connect together to form a longer suction tube. These are typically stored the same as previous suction tubes, along a side of the vessel. FR925946 discloses an example of this.

Other past suction tubes for use at greater depths are formed from a flexible hose, which can be wound around a reel when not in use. WO201103838 discloses such a system, which uses a flexible hose on a rotative reel with a rigid dredging head. The hose and dredging head are adapted to be lowered and elevated over one of the vessel sides by a hoisting means. Some suction tubes, such as the one shown in L8100267, work as two parallel suction tubes during operation, each suctioning up for the drag head. Thus, as they are working in parallel, they extend only as far as a single suction tube on one side would. SUMMARY

The present invention is directed toward an extended suction tube for a vessel, which includes a first portion which extends along the vessel in a length direction when not in use, a second portion which extends along the vessel in a width direction when not in use, and a third portion which extends along the vessel in a length direction when not in use. The first portion pivotally connects to the vessel when in use, the second portion pivotally connects to the first portion on a first end and to the third portion on a second end.

By forming the extended suction tube from three pivotally connected portions which extend along the vessel in a length, width and length direction, respectively, when not in use, suction tube can reach a seabed at great depths without losing steerability. According to an embodiment, when the extended suction tube is not in use, the first portion is stored on a first side of the vessel and the third portion is stored on a second side of the vessel.

According to an embodiment, when the extended suction tube is in use, the first portion extends from the vessel toward the second portion, the second portion connects the first portion and the third portion, and the third portion extends toward the seabed.

According to an embodiment, when the extended suction tube is in use, the second portion extends substantially horizontally from the first portion to the third portion.

According to an embodiment, when the extended suction tube is in use, the first portion extends downward at an angle in a first direction in relation to the direction of travel of the vessel and the third portion extends downward at an angle in an opposite direction to the first direction. By extending the first and third portions in opposite directions, the suction tube can be more controllable. This can also result in less stress on connections than if each portion extended in the same direction. Additionally, connection of the suction tube to the vessel via the ropes can be easier by this configuration, for example, the connections of the sections remain on top and directly below the gantry. Optionally, the first direction can be with the direction of travel of the vessel.

According to an embodiment, at least one of the first portion, the second portion and the third portion are expandable.

Making the first, second and/or third section expandable, can enable easy movement of the extended suction tube from a storage position to a use position or from a use position to a storage position.

According to an embodiment, at least one of the first portion, the second portion and the third portion comprises an expandable section.

According to an embodiment, the expandable section comprises telescoping parts, bellows, and/or a rubber section.

According to an embodiment, the third portion connects to a draghead or a suction head.

According to an embodiment, at least one of the first portion, the second portion and the third portion comprises one or more joints or hinges.

According to an embodiment, at least one of the first portion, the second portion and the third portion comprises one or more pumps.

According to an embodiment, the extended suction tube can be lowered to a use position by one or more gantries.

According to an embodiment, the vessel is a trailing suction hopper dredger.

The invention further relates to a method of suctioning a seabed with an extended suction tube. The extended suction tube comprises a first portion connected to a vessel and extending along the vessel in a length direction when not in use, a second portion connected to the first portion and extending along the vessel in a width direction when not in use and a third portion connected to the second portion on a first end and connected to a draghead on a second end and extending along a length of the vessel when not in use. The method comprises lowering the first, second and third portions of the extended suction tube toward the seabed so that the draghead contacts the seabed; and suctioning the seabed through the third portion, second portion and first portions of the extended suction tube.

According to an embodiment, the step of lowering the first, second and third portions comprises lowering the first, second and third portions of the extended suction tube toward the seabed so that the first portion extends toward the seabed from the vessel, the second portion extends substantially horizontally and the third portion extends toward the seabed and the draghead contacts the seabed.

According to an embodiment, the first portion extends downward in a first direction in relation to a direction of travel of the vessel, and the third portion extends downward in a direction opposite to the first direction.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 A illustrates a vessel with an extended suction tube.

FIG. IB schematically illustrates an example vessel with an extended suction tube in a storage position.

FIG. 1C schematically illustrates a perspective view of the vessel and extended suction tube of FIG. 1 A in a use position.

FIG. 2A schematically illustrates a second embodiment of a vessel with an extended suction tube in a storage position.

FIG. 2B schematically illustrates a side view of the vessel and extended suction tube of FIG. 2A in a use position.

FIG. 3 schematically illustrates a third embodiment of a vessel with an extended suction tube in a storage position.

FIG. 4A schematically illustrates a fourth embodiment of a vessel with an extended suction tube in a storage position.

FIG. 4B schematically illustrates the embodiment of FIG. 5 A in an extended position for lowering for use. DETAILED DESCRIPTION

FIG. 1 A illustrates vessel 10 with extended suction tube 12 in a use position in water body 14 from a side view. FIG. IB schematically illustrates vessel 10 with extended suction tube 12 in a storage position, and FIG. 1C schematically illustrates a perspective view of vessel 10 and extended suction tube 12 in a use position.

In use, suction tube 12 is pivotally connected to vessel 10 and includes first portion 16, second portion 18 and third portion 20. Draghead 22 is connected to third portion 20. In the embodiment shown, third portion 20 includes a pump 23. The connections between first portion 16, second portion 18, third portion 20 and draghead 22 can be pivotal connections. Vessel 10 includes one or more gantries 25 with rope 26 connected to suction tube 12 for lowering and raising suction tube 12. The position, number and placement of gantries and rope 26 are for example purposes only, and other

embodiments could have different numbers, positions and/or types of devices for raising and lowering suction tube 12. Additionally, while pump 23 is shown connected to third portion 20 in this embodiment, other embodiments could have one or more pumps connected to any portion or no pumps directly connected to suction tube 12. When not in use, suction tube 12 is stored on vessel 10 as shown in FIG. IB.

Specifically, first portion 16 is stored along a first side of vessel 10 in a length direction, second portion 18 is stored along vessel 10 in a width direction, and third portion is stored along a second side of vessel 10 in a length direction. In the embodiment shown, ship is sailing in a backwards direction as indicated by arrow M. Suction head is 22 is drug over seabed 24 by vessel 10. Therefore, in this embodiment, when in a storage position, first portion 16 is stored on starboard side of vessel 10 and third portion 20 is stored on port side of vessel 10. Second portion 18 is stored on the aft side of vessel 10. First, second and third portions 16, 18 and 20 can be placed directly on a deck of vessel 10 or can be stored elsewhere, for example, outside the outer contours of vessel 10.

In use, as shown in FIGS. 1 A and 1C, suction tube 12 extends from vessel 10 toward the sea bed 24 so that draghead 22 contacts seabed 24. First portion 16 extends toward the seabed 24 in a first direction in relation to the direction of travel, and is lowered and held by gantry 25 and rope 26 extending from one side of vessel 10. The first direction in which first portion 16 extends is typically with the direction of travel of vessel 10. Second portion 18 extends substantially horizontal from first portion 16, and third portion 20 extends from second portion 18 toward the seabed 24 in a second direction and is lowered and held by gantry 25 on the other side of vessel 10 and rope 26. The second direction in which third portion 20 extends is typically opposite to the first direction, so opposite to the direction of travel as indicated by arrow M.

In operation, suction tube 12 extends to a depth sufficient for draghead 22 to contact seabed 24. Draghead 22 then sucks up solids mixed with water from seabed 24. The mixture goes through third portion 20, second portion 18 and first portion 16 to vessel 10. Extended suction tube 12 allows for the suctioning of solid material mixed with water at greater depths than past suction tubes while providing similar steerability for movement as past single portion suction tubes. In past systems, the length of a rigid suction tube, and therefore the dredging depth, was limited by the length of the vessel. To dredge at deeper depths, telescopic suction tubes or flexible suction hoses were sometimes used. Telescopic suction tubes added a lot of weight to one side of the ship, and the gained dredge depth using telescopic suction tubes was limited to about 33% extra. Flexible suction hoses were able to extend further, but have less steerability than rigid tubes. Additionally, flexible suction hoses require a reel on the vessel deck, and many vessels do not have the space for that.

By forming extended suction tube 12 with a first portion 16 extending along a first side of the vessel in a length direction, a second portion 18 extending in a width direction of the vessel and a third portion 20 extending along a side of the vessel in a length direction; and connecting these with pivoting connections, suction tube 12 can reach great depths and still provide steerability similar to past rigid suction tubes.

Furthermore, extended suction tube 12 can increase the possible suction depth without requiring the additional deck space for storage that past longer suction tubes needed, for example, a flexible hose with a reel. By keeping second portion 18 substantially horizontal and lowering first portion 16 and third portion 20 to extend in opposite directions in relation to the direction of travel, suction tube 12 can reach depths approximately twice as great as past rigid suction tubes and provide high steerability. FIG. 2 A schematically illustrates an example vessel 10 with an extended suction tube 12 in a storage position, and FIG. 2B schematically illustrates a side view of the vessel 10 and extended suction tube 12 in a use position. Vessel 10 and suction tube 12 include the same basic parts and modes of operation as those shown in FIGS. 1A-1C. Specifically, extended suction tube 12 includes first portion 16, second portion 18 and third portion 20 which are pivotally connected to each other and to vessel 10 when in use. Draghead 22 is connected to third portion 20.

In the embodiment of FIGS. 2A-2B, vessel 10 moves in a forward direction of travel indicated by the arrow M. First portion 16 extends downward in the direction of arrow M and third portion 20 extends downward in a direction opposite to the direction of arrow M, the direction of travel. FIG. 3 schematically illustrates a third embodiment of vessel 10 with an extended suction tube 12 in a storage position. Extended suction tube 12 includes first portion 16 with joint 27, second portion 18 and third portion 20 with joint 27. Draghead 22 connects to third portion 20.

In the embodiment of FIG. 3, joints 27 allow first and third portions 16, 20 of suction tube 12 to flex outward to accommodate second portion 18 which is wider than vessel 10. Second portion 18 and outwardly flexed parts of first and third portions 16, 20 can be stored outside the outer contours of the ship to enable easier movement to a use position. As with the embodiment shown in FIG. 1 A, this can be done using gantries 25 and ropes 26 or any other means known in the art. While FIG. 3 shows an embodiment with first portion 16 and third portion 20 having a joint 27, in another embodiment, first portion 16 could have a flexible joint 27. This could be in addition to or in replacement from any other joints in any other sections and/or first section 16. This joint 27 could be flexible in many directions, for example, horizontally for easier launching and/or vertically to adapt to an uneven seabed. This could enable more stability for first portion 16, promoting good steerability despite challenging seabed conditions, such as a very uneven sea bed 24.

FIG. 4 A schematically illustrates an embodiment of a vessel 10 with extended suction tube 12 in a storage position, and FIG. 4B schematically illustrates the embodiment of FIG. 4 A in an extended position for lowering for use.

In this embodiment, each of first portion 16, second portion 18 and third portion 20 are expandable in length through expandable sections 28. Expandable sections 28 can be any combination of telescoping parts, bellows, expandable material such as rubber or other means. As shown in FIG. 4A, expandable sections 28 allow for the lengthening of first portion 16, second portion 18 and third portion 20. This can enable easier movement from a storage position on a deck of vessel 10 (FIG. 4 A) to a use position. By using small expandable sections 28 on each of first, second and third portions 16, 18 and 20, suction tube 12 can easily expand the length of each portion to move suction tube 12 off the deck of vessel 10 and lower to a use position. Expansion means 28 are relatively small in relation to the length of each portion, thereby not adding significant weight or stress to any single portion of suction tube 12.

In summary, suction tube 12 can allow for suctioning at greater depths without decreasing the steerability by using a plurality of rigid portions 16, 18, 20 which pivotally connect together and are stored on vessel 10 when not in use. By storing first and third portions 16, 20 along a first and second side of vessel 10 in a length direction, with second portion 18 connected them in a width direction, suction tube 12 is not limited to a dredging depth determined by a single length of vessel 10. Additionally, past rigid suction tubes could be adapted for use in extended suction tube 12. Past single length suction tubes could form first portion 16 and/or third portion 20. The draghead could be taken detached from the past suction tube, and it could be pivotally connected to a second portion 18 to form extended suction tube 12.

By keeping second portion 18 substantially horizontal during use and lowering first portion 16 and third portion 20 to extend in opposite directions in relation to the direction of travel, suction tube 12 can reach depths approximately twice as great as past rigid suction tubes and provide similar steerability to past rigid suction tubes. First, second, and/or third portions 16, 18, 20 can also be expandable and/or include expansion sections to enable easier movement from a storage to a use position and vice versa.

While extended suction tube 12 is shown in use with second portion 18 substantially horizontal, second portion 18 can extend in a direction that is not substantially horizontal.

While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

CLAIMS:

1. An extended suction tube for a vessel, the extended suction tube comprising: a first portion which extends along the vessel in a length direction when not in use and pivotally connects to the vessel when in use;

a second portion which extends along the vessel in a width direction when not in use, the second portion with a first end pivotally connected to the first portion and a second end; and

a third portion which extends along the vessel in a length direction when not in use and is pivotally connected to the second end of the second portion.

2. The extended suction tube of claim 1, wherein when the extended suction tube is not in use, the first portion is stored on a first side of the vessel and the third portion is stored on a second side of the vessel.

3. The extended suction tube of any of the preceding claims, wherein when the extended suction tube is in use, the first portion extends from the vessel toward the second portion, the second portion connects the first portion and the third portion, and the third portion extends toward a seabed.

4. The extended suction tube of any of the preceding claims, wherein when the extended suction tube is in use, the second portion extends substantially horizontally from the first portion to the third portion.

5. The extended suction tube of any of the preceding claims, wherein when the extended suction tube is in use, the first portion extends downward at an angle in a first direction in relation to the direction of travel of the vessel and the third portion extends downward at an angle in an opposite direction to the first direction.

6. The extended suction tube of claim 5, wherein the first direction is the direction of travel of the vessel.

7. The extended suction tube of any of the preceding claims, wherein at least one of the first portion, the second portion and the third portion are expandable.

8. The extended suction tube of claim 7, wherein the at least one of the first portion, the second portion and the third portion comprises an expandable section.

9. The extended suction tube of claim 8, wherein the expandable section comprises telescoping parts.

10. The extended suction tube of claim 8, wherein the expandable section comprises bellows.

11. The extended suction tube of claim 8, wherein the expandable section comprises a rubber section.

12. The extended suction tube of any of the preceding claims, wherein the third portion connects to a draghead.

13. The extended suction tube of any of the preceding claims, wherein the extended suction tube can be lowered to a use position by one or more gantries.

14. The extended suction tube of any of the preceding claims, and further comprising a pump on at least one of the first portion, the second portion and the third portion.

15. A trailing suction hopper dredger with an extended suction tube according to any of claims 1-14.

16. A method of suctioning a seabed with an extended suction tube comprising a first portion connected to a vessel and extending along the vessel in a length direction when not in use, a second portion connected to the first portion and extending along the vessel in a width direction when not in use and a third portion connected to the second portion on a first end and connected to a draghead on a second end and extending along the vessel in a length direction when not in use, the method comprising:

lowering the first, second and third portions of the extended suction tube toward the seabed so that the draghead contacts the seabed; and

suctioning the seabed through the third portion, second portion and first portion of the extended suction tube.

17. The method of claim 16, wherein the step of lowering the first, second and third portions comprises lowering the first, second and third portions of the extended suction tube toward the seabed so that the first portion extends toward the seabed from the vessel, the second portion extends substantially horizontally, the third portion extends toward the seabed and the draghead contacts the seabed.

18. The method of any of claims 16-17, wherein the first portion extends downward in a first direction in relation to a direction of travel of the vessel, and the third portion extends downward in a direction opposite to the first direction.