US20150233088A1 - Trenching device - Google Patents
Trenching device Download PDFInfo
- Publication number
- US20150233088A1 US20150233088A1 US14/420,596 US201314420596A US2015233088A1 US 20150233088 A1 US20150233088 A1 US 20150233088A1 US 201314420596 A US201314420596 A US 201314420596A US 2015233088 A1 US2015233088 A1 US 2015233088A1
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- US
- United States
- Prior art keywords
- trenching
- wheel
- seabed
- ballast
- trenching device
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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- 238000000034 method Methods 0.000 claims description 78
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 24
- 230000007423 decrease Effects 0.000 claims description 10
- 239000012530 fluid Substances 0.000 claims description 5
- 239000002689 soil Substances 0.000 description 36
- 239000003643 water by type Substances 0.000 description 3
- 238000009933 burial Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000008092 positive effect Effects 0.000 description 2
- 239000000428 dust Substances 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F5/00—Dredgers or soil-shifting machines for special purposes
- E02F5/02—Dredgers or soil-shifting machines for special purposes for digging trenches or ditches
- E02F5/10—Dredgers or soil-shifting machines for special purposes for digging trenches or ditches with arrangements for reinforcing trenches or ditches; with arrangements for making or assembling conduits or for laying conduits or cables
- E02F5/104—Dredgers or soil-shifting machines for special purposes for digging trenches or ditches with arrangements for reinforcing trenches or ditches; with arrangements for making or assembling conduits or for laying conduits or cables for burying conduits or cables in trenches under water
- E02F5/105—Dredgers or soil-shifting machines for special purposes for digging trenches or ditches with arrangements for reinforcing trenches or ditches; with arrangements for making or assembling conduits or for laying conduits or cables for burying conduits or cables in trenches under water self-propulsed units moving on the underwater bottom
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F5/00—Dredgers or soil-shifting machines for special purposes
- E02F5/02—Dredgers or soil-shifting machines for special purposes for digging trenches or ditches
- E02F5/08—Dredgers or soil-shifting machines for special purposes for digging trenches or ditches with digging wheels turning round an axis
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F5/00—Dredgers or soil-shifting machines for special purposes
- E02F5/02—Dredgers or soil-shifting machines for special purposes for digging trenches or ditches
- E02F5/10—Dredgers or soil-shifting machines for special purposes for digging trenches or ditches with arrangements for reinforcing trenches or ditches; with arrangements for making or assembling conduits or for laying conduits or cables
- E02F5/104—Dredgers or soil-shifting machines for special purposes for digging trenches or ditches with arrangements for reinforcing trenches or ditches; with arrangements for making or assembling conduits or for laying conduits or cables for burying conduits or cables in trenches under water
- E02F5/109—Dredgers or soil-shifting machines for special purposes for digging trenches or ditches with arrangements for reinforcing trenches or ditches; with arrangements for making or assembling conduits or for laying conduits or cables for burying conduits or cables in trenches under water using rotating digging elements
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F5/00—Dredgers or soil-shifting machines for special purposes
- E02F5/02—Dredgers or soil-shifting machines for special purposes for digging trenches or ditches
- E02F5/14—Component parts for trench excavators, e.g. indicating devices travelling gear chassis, supports, skids
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/02—Travelling-gear, e.g. associated with slewing gears
- E02F9/024—Travelling-gear, e.g. associated with slewing gears with laterally or vertically adjustable wheels or tracks
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/02—Travelling-gear, e.g. associated with slewing gears
- E02F9/026—Travelling-gear, e.g. associated with slewing gears for moving on the underwater bottom
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/08—Superstructures; Supports for superstructures
- E02F9/0841—Articulated frame, i.e. having at least one pivot point between two travelling gear units
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/18—Counterweights
Definitions
- the invention relates to the forming of a trench in a seabed to receive an elongate object, such as a pipeline.
- Shallow Arctic waters are characterized by the occurrence of ice ridges which may hit the seabed in typical water depths between 10 and 60 meters and form deep gouges into the soil. Pipelines crossing such ice ridge zones must be buried deeply below the seabed to avoid damage as a result of ice ridge loading. Typical burial depths against ice ridges are 4 to 6 meters.
- Icebergs may occur. Icebergs are heavier than ice ridges and may have a draft of 200 to 300 meters. Icebergs may touch the seabed in water depths as deep as 200 to 300 meters and form even deeper gouges than ice ridges. Typical pipeline burial depths against ice bergs may be as deep as 5 to 8 meters.
- the trench For protection against ice ridge or iceberg loading, the trench must be backfilled after the pipeline has been laid in it.
- the seabed in Arctic offshore regions frequently contain hard glacial over-consolidated soils with frequent occurrence of boulders. Occasionally, lenses of permafrost may occur.
- the hard soils may be covered by a few meters of soft Holocene soils.
- the surface of the seabed is very uneven as a result of gouges and berms formed in the past. Gouges may be as deep as 2 to 4 meters below the average seabed and berms as high as 2 meters above it.
- the gouges may be filled with loose sands and silts.
- a trenching device for forming a trench in a seabed to receive an elongate object, such as a pipeline, said trenching device comprising a base frame, and a trenching wheel which is connected to the base frame and rotatable about a trenching wheel axis to form the trench, wherein the trenching device is configured to push the trenching wheel into the seabed when the trenching wheel is positioned on the seabed.
- the trenching device is configured to push the soil of the seabed away with the trenching wheel to form the trench, without conveying excavated soil of the seabed out of the trench
- the trenching device is configured to form the trench by only pushing the soil of the seabed away with the rotating trenching wheel when the trenching device is moved along the seabed.
- the trenching wheel rotates in the direction of movement of the trenching device.
- a ballast is provided to push the trenching wheel into the seabed when the trenching wheel is positioned on the seabed.
- the trenching wheel is configured and arranged to push the soil of the seabed to the side when the trenching device is moved along the seabed while the trenching wheel is pushed into the seabed.
- the trenching wheel comprises an outer circumference.
- the trenching wheel comprises a first side surface and an opposite second side surface, the trenching wheel is arranged such that the outer circumference is pushed into the seabed and the first side surface and second side surface push the soil of the seabed to the side when the trenching device is moved along the seabed.
- the trenching wheel comprises a radius R 1 which is larger than a depth D of the trench that is formed.
- the radius R 1 is between 5 and 15 m.
- the radius R 1 is between 10 and 12 m.
- the trenching device is configured to form a trench with a depth D between 1 and 8 m.
- the trenching device is configured to form a trench with a depth D of around 5 m.
- the trenching wheel axis in use extends parallel, or substantially parallel, to the seabed.
- the trenching wheel extends perpendicular from the base frame.
- the trenching wheel in use extends upwardly from the seabed.
- the outer circumference of the trenching wheel is rounded.
- the outer circumference of the trenching wheel is roughened to enhance friction between said outer circumference and the seabed.
- the trenching wheel in the direction of the trenching wheel axis, comprises a thickness and the thickness decreases in the direction from the trenching wheel axis to the outer circumference of the trenching wheel.
- the trenching wheel comprises a thickness t 1 near the trenching wheel axis and a thickness t 2 near the outer circumference of the trenching wheel, and the thickness decreases in the direction from the trenching wheel axis to the outer circumference of the trenching wheel.
- the trenching wheel comprises a thickness t 1 near the trenching wheel axis and a thickness t 2 near the outer circumference of the trenching wheel, and the thickness decreases in the direction from the trenching wheel axis to the outer circumference of the trenching wheel in a linear manner from t 1 to t 2 .
- t 1 is between 1.5 and 4 m and t 2 is between 1 and 2 m.
- the ballast is formed, or partly formed, by a fixed ballast member connected to the base frame in a fixed position.
- the ballast is formed, or partly formed, by a ballast system.
- the ballast system is configured to adjust the magnitude of the force working on the base frame.
- the ballast system is configured to adjust the position of the force working on the base frame.
- the ballast system comprises a ballast tank configured to hold a fluid.
- the ballast tank comprises multiple ballast compartments.
- the ballast system comprises a pump system to pump water and gas in the ballast tank.
- the pump system is configured to pump water and gas in multiple ballast compartments independently from each other.
- the ballast is formed, or partly formed, by the mass of the trenching wheel.
- the trenching wheel at the inside thereof is filled with a material to enhance the mass of the trenching wheel.
- the majority of the ballast is located above the trenching wheel axis.
- the trenching device comprises a front side and a rear side, the trenching device is configured to be moved in the direction from the rear side to the front side, the resultant force of the ballast acting on the base frame is located at a distance e beyond the trenching wheel axis when seen in the direction from the rear side to the front side.
- the trenching device comprises a propulsion system formed by at least one propulsion unit which is connected to the base frame to move the trenching device along the seabed.
- At least one propulsion unit comprises a wheel drive to rotate the trenching wheel around the trenching wheel axis in order to move the trenching device along the seabed.
- the base frame comprises a connector to connect the base frame to an external propulsion system for moving the trenching device along the seabed.
- the base frame comprises a length direction, and at least one propulsion unit is connected to the base frame at a distance from the trenching wheel in said length direction.
- At least one propulsion unit comprises an assisting wheel connected to the base frame and rotatable about an assisting wheel axis, and a further wheel drive to rotate the assisting wheel around the assisting wheel axis in order to move the trenching device along the seabed.
- the trenching wheel axis and the assisting wheel axis extend in one plane.
- At least one propulsion unit comprises a driven caterpillar track.
- the trenching wheel axis and the assisting wheel axis extend parallel, or substantially parallel, to each other.
- the assisting wheel axis in use extends parallel, or substantially parallel, to the seabed.
- the assisting wheel comprises an outer circumference.
- the outer circumference of the assisting wheel is rounded.
- the outer circumference of the assisting wheel is roughened to enhance friction between said outer circumference and the seabed.
- the assisting wheel in the direction of the assisting wheel axis comprises a thickness t 3 and the thickness t 3 remains constant in the direction from the assisting wheel axis to the outer circumference of the assisting wheel.
- the thickness t 3 equals t 2 .
- the thickness t 3 is larger than t 2 and smaller than t 1 .
- the thickness t 3 is larger than t 2 and smaller than t 2 +0.5(t 1 ⁇ t 2 ).
- the assisting wheel comprises a radius R 2 which equals R 1 .
- the base frame comprises a first frame part and a second frame part which are connected to each other via a pivot connection, the trenching wheel is connected to the first frame part, and at least one propulsion unit is connected to the second frame part.
- the second frame part is pivotable about a frame pivot axis relative to the first frame part, and the frame pivot axis extends perpendicular, or substantially perpendicular, to the trenching wheel axis.
- the trenching device comprises a steering system configured to pivot the second frame part relative to the first frame part.
- the base frame comprises a first frame side and an opposite second frame side and supports are connected to the first frame side and second frame side to hold the trenching wheel in an upwardly extending position.
- the supports are constructed to be positioned in contact with the seabed.
- At least one of the supports is provided with at least one propulsion unit.
- the height of the supports is adjustable to follow unevenness of the seabed.
- the trenching device comprises a further trenching wheel which is connected to the base frame and rotatable about a further trenching wheel axis to form the trench, and the trenching device is configured to push the further trenching wheel into the seabed when the further trenching wheel is positioned on the seabed.
- the trenching device comprises a further ballast to push the further trenching wheel into the seabed when the further trenching wheel is positioned on the seabed.
- the further trenching wheel comprises corresponding features of the trenching wheel as defined in any of the claims 3 - 12 .
- the further ballast comprises corresponding features of the ballast as defined in any of the claims 13 - 23 .
- the trenching device is configured to push the trenching wheel over a first distance D 1 into the seabed and to push the further trenching wheel over a second distance D 2 into the seabed.
- the distance D 2 is larger than the distance D 1 .
- the invention further relates to a method of forming a trench in a seabed to receive an elongate object, such as a pipeline, with a trenching device comprising a base frame, a trenching wheel which is connected to the base frame and rotatable about a trenching wheel axis to form the trench, wherein the trenching device is configured to push the trenching wheel into the seabed when the trenching wheel is positioned on the seabed and said method comprises positioning the trenching wheel on the seabed, pushing the trenching wheel into the seabed, and moving the trenching device along the seabed to form the trench.
- a trenching device comprising a base frame, a trenching wheel which is connected to the base frame and rotatable about a trenching wheel axis to form the trench, wherein the trenching device is configured to push the trenching wheel into the seabed when the trenching wheel is positioned on the seabed and said method comprises positioning the trenching wheel on the seabed, pushing the trenching wheel into the seabed, and moving the trenching device along
- the method comprises pushing the soil of the seabed away with the trenching wheel to form the trench, without conveying excavated soil out of the trench.
- the method comprises forming the trench by only pushing the soil of the seabed away with the rotating trenching wheel when the trenching device is moved along the seabed.
- the method comprises rotating the trenching wheel in the direction of movement of the trenching device.
- the trenching device comprises a ballast and the method comprises pushing the trenching wheel into the seabed by the weight of the ballast.
- the method comprises pushing the soil of the seabed to the side by moving the trenching device along the seabed while the trenching wheel is pushed into the seabed.
- the trenching wheel comprises an outer circumference, a first side surface and an opposite second side surface
- the method comprises pushing the outer circumference into the seabed and pushing the soil of the seabed to the side with the first side surface and the second side surface by moving the trenching device is along the seabed.
- the trenching device comprises a front side and a rear side and the method comprises moving the trenching device in the direction from the rear side to the front side.
- the ballast is formed, or partly formed, by a ballast system configured to adjust the magnitude and/or the position of the force of the ballast working on the base frame, and the method comprises adjusting the magnitude and/or the position of the force of the ballast working on the base frame to push the trenching wheel into the seabed.
- the ballast system comprises a ballast tank configured to hold a fluid and the method comprises filling the ballast tank with water to increase the magnitude of the force of the ballast working on the base frame.
- the ballast tank can be partly filled or completely filled with water.
- the ballast tank can be filled between 0 and 100% with water, depending on the required force of the ballast.
- the method comprises filling the ballast tank with air to decrease the magnitude of the force of the ballast working on the base frame and/or to create buoyancy such that the trenching device is neutrally buoyant or floats up in the water.
- the ballast tank can be partly filled or completely filled with gas.
- the ballast tank can be filled between 0 and 100% with gas.
- the trenching device comprises a propulsion system formed by at least one propulsion unit connected to the base frame and the method comprise moving the trenching device along the seabed with the propulsion system.
- At least one propulsion unit comprises a wheel drive to rotate the trenching wheel around the trenching wheel axis and the method comprises rotating the trenching wheel to move the trenching device along the seabed.
- the base frame comprises a length direction
- at least one propulsion unit is connected to the base frame at a distance from the trenching wheel in said length direction and the method comprises moving the trenching device along seabed with the propulsion unit.
- At least one propulsion unit comprises an assisting wheel connected to the base frame and rotatable about an assisting wheel axis and a further wheel drive to rotate the assisting wheel around the assisting wheel axis and the method comprise rotating the assisting wheel around the assisting wheel axis to move the trenching device along the seabed.
- the base frame comprises a first frame part and a second frame part which are connected to each other via a pivot connection
- the trenching wheel is connected to the first frame part
- at least one propulsion unit is connected to the second frame part
- the trenching device comprises a steering system configured to pivot the second frame part relative to the first frame part and the method comprises pivoting the second frame part relative to the first frame part to adjust the direction in which the trenching device is moved along the seabed.
- the trenching device comprises a further trenching wheel which is connected to the base frame and rotatable about a further trenching wheel axis to form the trench, and the trenching device is configured to push the further trenching wheel into the seabed when the further trenching wheel is positioned on the seabed and the method comprises pushing the trenching wheel over a first distance D 1 into the seabed and pushing the further trenching wheel over a second distance D 2 into the seabed, while the trenching device is moved along the seabed.
- the distance D 2 is larger than the distance D 1 .
- the invention further relates to a method of forming a trench in a seabed to receive an elongate object, such as a pipeline, with the trenching device according to the invention, wherein said method comprises positioning the trenching wheel on the seabed, pushing the trenching wheel into the seabed, and moving the trenching device along the seabed to form the trench.
- said method comprises the method steps defined in any of the claims 45 - 59 .
- the invention further relates to a use of the trenching device according to the invention to form a trench in a seabed.
- FIG. 1 schematically shows a side view of a first embodiment of the trenching device and method
- FIG. 2 schematically shows a view in cross section along line II-II of the trenching device of FIG. 1 ,
- FIG. 3 schematically shows a side view of the trenching wheel of FIG. 1 .
- FIG. 4 schematically shows a side view a second embodiment of the trenching device and method
- FIG. 5 schematically shows a view in cross section along line V-V of the trenching device of FIG. 4 .
- FIG. 6 schematically shows a side view of the trenching wheel of FIG. 4 .
- FIG. 7 schematically shows a side view of a third embodiment of the trenching device and method
- FIG. 8 schematically shows a side view of a fourth embodiment of the trenching device and method
- FIG. 9 schematically shows a side view of a fifth embodiment of the trenching device and method
- FIG. 10 schematically shows a side view of a sixth embodiment of the trenching device and method
- FIGS. 11 and 12 schematically show a top view of a seventh embodiment of the trenching device and method
- FIG. 13 schematically shows a side view of a eight embodiment of the trenching device and method
- FIG. 14 schematically shows a view in cross section along line X-X of the trenching device of FIG. 13 .
- FIG. 15 schematically shows a side view of a ninth embodiment of the trenching device and method.
- the FIG. 1 shows a side view of a first embodiment of the trenching device and method.
- the trenching device 1 is forming a trench 2 in a seabed 3 to receive an elongate object, such as a pipeline.
- the trenching device 1 comprises a base frame 6 , and a trenching wheel 7 which is connected to the base frame 6 and rotatable about a trenching wheel axis 8 to form the trench 2 .
- the trenching device 1 is configured to push the trenching wheel 7 into the seabed 3 when the trenching wheel 7 is positioned on the seabed 3 . This means that the trench is formed without ploughing, excavating, jetting or suction cutting.
- the trenching device 1 is configured to push the soil of the seabed 3 away with the trenching wheel 7 to form the trench 2 , without conveying excavated soil of the seabed 3 out of the trench 2 .
- the trenching device 1 is configured to form the trench 2 by only pushing the soil of the seabed 3 away with the rotating trenching wheel 7 when the trenching device 1 is moved along the seabed 3 .
- the trenching wheel 7 is rotated in the direction of movement of the trenching device 1 .
- the rotation of the trenching wheel 7 is indicated by arrow 24 .
- a ballast 9 is provided to push the trenching wheel 7 into the seabed 3 when the trenching wheel 7 is positioned on the seabed 3 .
- the trenching wheel 7 is configured and arranged to push the soil of the seabed 3 to the side when the trenching device 1 is moved along the seabed 3 while the trenching wheel 7 is pushed into the seabed 3 by the ballast 9 .
- the trenching wheel 7 comprises an outer circumference 13 .
- the trenching wheel 7 comprises a first side surface 4 and an opposite second side surface 5 , the trenching wheel 7 is arranged such that the ballast 9 pushes the outer circumference 13 into the seabed 3 and the first side surface 4 and second side surface 5 push the soil of the seabed 3 to the side when the trenching device 1 is moved along the seabed 3 .
- the trenching device 1 comprises a front side 18 and a rear side 19 . The trenching device 1 is moved in the direction from the rear side 19 to the front side 18 , as indicated by arrow 20 .
- the trenching wheel 7 comprises a radius R 1 which is larger than a depth D of the trench 2 that is formed.
- the radius R 1 is around 10 m. In other examples of the trenching device 1 , the radius R 1 is between 5 and 15 m.
- the depth D of the trench 2 is around 5 m. In other examples the trenching device 1 is configured to form a trench with a depth D between 1 and 8 m.
- the trenching wheel axis 8 extends parallel, or substantially parallel, to the seabed 3 .
- the trenching wheel 7 extends perpendicular from the base frame 6 .
- the trenching wheel 7 extends upwardly from the seabed 3 .
- the ballast 9 is formed by a fixed ballast member 14 connected to the base frame 6 in a fixed position and by a ballast system 15 .
- the ballast system 15 is configured to adjust the magnitude and the position of the force working on the base frame 6 . This means that the amount of Newton the ballast system 15 subjects to the base frame 6 can be controlled. Also the position where the force of the ballast system 15 is subjected on base frame 6 can be controlled. In other examples of the trenching device 1 , only the magnitude or the position of the force of the ballast system 15 working on the base frame 6 can be adjusted.
- the ballast system 15 comprises a ballast tank 16 configured to hold a fluid.
- the ballast tank 16 can hold liquid and gas.
- the ballast tank 16 comprises multiple ballast compartments 34 .
- the ballast system 15 comprises a pump system 17 to pump either water and gas in the ballast tank 16 .
- the pump system 17 is configured to pump water and gas in the multiple ballast compartments 34 independently from each other.
- Each ballast compartment 34 can be filled between 0 and 100% with water, independently from each other.
- Each ballast compartment 34 can be filled between 0 and 100% with gas, independently from each other.
- the ballast compartments 34 are positioned next to each other along the base frame 6 .
- the majority of the ballast 9 is located beyond the trenching wheel axis 8 when seen in the direction from the rear side 19 to the front side 18 .
- the resultant force Fr of the ballast 9 acting on the base frame 6 is located beyond the trenching wheel axis 8 when seen in the direction from the rear side 19 to the front side 18 .
- the resultant force Fr of the ballast 9 acting on the base frame 6 is located at a distance e beyond the trenching wheel axis 8 when seen in the direction from the rear side 19 to the front side 18 .
- the ballast 9 is located above the trenching wheel axis 8 .
- the majority of the ballast 9 is located above the trenching wheel axis 8 .
- the ballast 9 is formed, or partly formed, by the mass of the trenching wheel 7 .
- the trenching wheel 7 is constructed to have a large mass.
- the inside of the trenching wheel 7 can for example be filled with a material, such a concrete, to enhance the mass of the trenching wheel 7 .
- the trenching device 1 comprises a propulsion system formed by a propulsion unit 11 which is connected to the base frame 6 to move the trenching device 1 along the seabed 3 .
- the propulsion unit 11 comprises a wheel drive 10 to rotate the trenching wheel 7 around the trenching wheel axis 8 in order to move the trenching device 1 along the seabed 3 .
- the base frame 6 comprises a connector 21 to connect the base frame 6 to an external propulsion system 12 , such as a vessel, for moving the trenching device 1 along the seabed 3 .
- an external propulsion system 12 such as a vessel
- the propulsion system comprises multiple propulsion units.
- ballast system 15 (comprising the pump system 17 ) are controlled by a control system 45 provided on the base frame 6 .
- FIG. 2 shows a view in cross section along line II-II of the trenching device 1 .
- the trenching wheel 7 comprises an outer circumference 13 .
- the outer circumference 13 forms a transition from the first side surface 4 and the second side surface 5 .
- the outer circumference 13 of the trenching wheel 7 is rounded.
- the outer circumference 13 is rounded in the direction from the first side surface 4 to the second side surface 5 .
- the rounded outer circumference 13 increases the surface area of the outer circumference 13 and therefore enhances the friction between the outer circumference 13 and the soil of the seabed 3 when the trenching wheel 7 is driven around the trenching wheel axis 8 .
- the outer circumference 13 of the trenching wheel 7 is roughened to enhance the friction between said outer circumference 13 and the seabed 3 .
- the trenching wheel 7 comprises a thickness and the thickness decreases in the direction from the trenching wheel axis 8 to the outer circumference 13 of the trenching wheel 7 .
- Said form of the trenching wheel 7 facilitates the forming of the trench.
- the trenching wheel 7 comprises a thickness t 1 near the trenching wheel axis 8 and a thickness t 2 near the outer circumference 13 of the trenching wheel 7 .
- the thickness decreases in the direction from the trenching wheel axis 8 to the outer circumference 13 of the trenching wheel 7 .
- the thickness decreases in a linear manner from t 1 to t 2 .
- the thickness t 1 is around 3 m and t 2 is around 1.5 m.
- the thickness decreases in a non-linear manner from t 1 to t 2 .
- the thickness t 1 is between 1.5 and 4 m and t 2 is between 1 and 2 m.
- the bottom of the trench 2 has a width of at least 1 m.
- the method of forming the trench 2 in the seabed 3 to receive an elongate object, such as a pipeline, with the trenching device 1 comprises positioning the trenching wheel 7 on the seabed 3 , pushing the trenching wheel 7 into the seabed 3 by the weight of the ballast 9 , moving the trenching device 1 along the seabed 3 to form the trench.
- the soil of the seabed 3 is pushed to the side by moving the trenching device 1 along the seabed 3 while the trenching wheel 7 is pushed into the seabed 3 by the ballast 9 .
- the outer circumference 13 of the trenching wheel 7 is pushed into the seabed 3 by the ballast 9 and the soil of the seabed 3 is pushed to the side with the first side surface 4 and the second side surface 5 by moving the trenching device 1 is along the seabed 3 .
- the trenching device 1 is moved in the direction from the rear side 19 to the front side 18 .
- the trenching device 1 is moved along the seabed 3 with the propulsion system.
- the trenching wheel 7 is rotated to move the trenching device 1 along the seabed 3 .
- the magnitude and the position of the force of the ballast 9 working on the base frame 6 to push to trenching wheel 7 into the seabed 3 can be adjusted.
- the ballast tank 16 can be filled with water to increase the magnitude of the force of the ballast 9 working on the base frame 6 .
- the ballast tank 16 can be filled between 0 and 100% with water, depending on the required force of the ballast 9 .
- the ballast tank 16 can be filled with air to decrease the magnitude of the force of the ballast 9 working on the base frame 6 . This way, the magnitude of the force can be adjusted to the hardness of the soil in which the trench 2 is formed. Harder soils require a large force, whereas softer soil require a smaller force.
- the ballast tank 16 can be filled with air to create buoyancy such that the trenching device 1 is neutrally buoyant or floats up in the water.
- the ballast system 15 is configured position the trenching device 1 in a horizontal, or substantially horizontal, position when floating at the water surface or under the water surface.
- the ballast tank 16 can be filled between 0 and 100% with gas.
- FIG. 3 shows a side view of the trenching wheel 7 of FIG. 1 being moved in the direction 20 along the seabed 3 while being pushed into the seabed 3 by the ballast 9 . Due to the form of the trenching wheel 7 , only a relatively small part first side surface 4 and second side surface 5 of the trenching wheel 7 will be in contact with the soil of the seabed 3 . Only the indicated friction area 37 of the trenching wheel 7 will be in contact with the soil of the seabed 3 . This tends to have a positive effect on the friction of the soil of the seabed 3 which the trenching device 1 experiences when forming the trench.
- FIG. 4 shows a side view a second embodiment of the trenching device 1 and method.
- the trenching device 1 of FIG. 4 differs from the one in FIG. 1 in that it does not comprises a connector 21 and in that an additional propulsion unit 11 B formed by an assisting wheel 23 is provided.
- a connector 21 can be provided in combination with the assisting wheel 23 or a different type of additional propulsion unit 11 B.
- the propulsion system only comprises the driven assisting wheel 23 .
- the base frame 6 comprises a length direction 22
- the additional propulsion unit 11 B is connected to the base frame 6 at a distance from the trenching wheel 7 in said length direction 22 .
- the additional propulsion unit 11 comprises an assisting wheel 23 connected to the base frame 6 and rotatable about an assisting wheel axis 33 , and a further wheel drive 10 B to rotate the assisting wheel 23 around the assisting wheel axis 33 in order to move the trenching device 1 along the seabed 3 .
- the trenching wheel 7 and the assisting wheel 23 rotate in the direction of the arrows 24 A and 24 B, respectively.
- the trenching wheel axis 8 and the assisting wheel axis 33 extend in one plane.
- the trenching wheel axis 8 and the assisting wheel axis 33 extend parallel to each other.
- the assisting wheel axis 33 extends parallel, or substantially parallel, to the seabed 3 .
- the assisting wheel 23 extends perpendicular from the base frame 6 .
- the assisting wheel 23 in use extends upwardly from the seabed 3 .
- the operations of the propulsion system (formed by the propulsion units 11 A, 11 B) and ballast system 15 (comprising the pump system 17 ) are controlled by a control system 45 provided on the base frame 6 .
- FIG. 5 shows a view in cross section along line V-V of the trenching device 1 of FIG. 4 .
- the assisting wheel 23 comprises an outer circumference 35 , a first side surface 39 and a second side surface 40 .
- the outer circumference 35 of the assisting wheel 23 is rounded.
- the outer circumference 35 of the assisting wheel 23 is rounded in a similar manner as the outer circumference 13 of the trenching wheel 7 is rounded.
- the outer circumference 35 of the assisting wheel 23 is roughened to enhance friction between said outer circumference 35 and the soil of the seabed 3 .
- the assisting wheel 23 comprises a thickness t 3 and the thickness t 3 remains constant in the direction from the assisting wheel axis 33 to the outer circumference 35 of the assisting wheel 23 .
- the thickness t 3 is around 1.5 In other examples of the trenching device 1 , the thickness t 3 is larger than t 2 and smaller than t 2 +0.5(t 1 ⁇ t 2 ).
- the assisting wheel 23 comprises a radius R 2 which equals R 1 . In other examples of the trenching device 1 , the assisting wheel 23 comprises a radius R 2 which differs from R 1 .
- FIG. 6 shows a side view of the trenching wheel 7 of FIG. 4 being moved through the trench. Due to the form of the assisting wheel 23 , only a relatively small part of the first side surface 39 and second side surface 40 of the assisting wheel 23 will be in contact with the soil of the seabed 3 . Only the indicated friction area 38 of the assisting wheel 23 will be in contact with the soil of the seabed 3 . This tends to have a positive effect on the friction of the soil of the seabed 3 which the trenching device 1 experiences when forming the trench.
- the trenching device 1 is configured to form a trench with a length of around 10 km a day.
- the method of forming the trench 2 in the seabed 3 comprises rotating the assisting wheel 23 around the assisting wheel axis 33 to move the trenching device 1 along the seabed 3 .
- FIG. 7 shows a side view of a third embodiment of the trenching device and method.
- the trenching device 1 differs from the one shown in FIG. 4 , in that a further ballast 9 B is provided at the assisting wheel 23 .
- the further ballast 9 B comprises two fixed further ballast members 14 B and a further ballast system 15 B.
- the further ballast system 15 B has the same or corresponding design as the ballast system 15 A.
- the further ballast 9 B allows to enhance the grip that the assisting wheel 23 has on the soil of the seabed 3 .
- the operations of the further ballast system 15 B is also controlled by the control system 45 .
- FIG. 8 shows a side view of a fourth embodiment of the trenching device and method.
- the trenching device 1 comprises a further trenching wheel 7 B which is connected to the base frame 6 and rotatable about a further trenching wheel axis 8 B to form the trench 2 , and the trenching device 1 is configured to push the further trenching wheel 7 B into the seabed 3 when the further trenching wheel 7 B is positioned on the seabed 3 .
- the trenching device 1 comprises a further ballast 9 B to push the further trenching wheel 7 B into the seabed 3 when the further trenching wheel 7 B is positioned on the seabed 3 .
- the further trenching wheel 7 B has the same or corresponding design as the trenching wheel 7 A.
- the further ballast system 15 B has the same or corresponding design as the ballast system 15 A.
- the trenching device 1 is configured to push the trenching wheel 7 A over a first distance D 1 into the seabed and to push the further trenching wheel 7 B over a second distance D 2 into the seabed.
- the distance D 2 is larger than the distance D 1 .
- the method of forming a trench comprises pushing the trenching wheel 7 A over a first distance D 1 into the seabed and pushing the further trenching wheel 7 B over a second distance D 2 into the seabed, while the trenching device 1 is moved along the seabed 3 .
- the trenching device 1 comprises multiple trenching wheels 7 in combination with one or more assisting wheels 23 .
- FIG. 9 shows a side view of a fifth embodiment of the trenching device and method.
- the trenching device 1 differs from the one shown in FIG. 8 , in that trenching wheel axis 8 A is positioned higher in the vertical direction relative to the further trenching wheel axis 8 B.
- the trenching device is configured to adjust the position of the trenching wheel axis 8 A in the vertical direction relative to the base frame 6 .
- the position of the further trenching wheel axis 8 B is in the vertical direction also adjustable relative to the base frame 6 .
- only the position of the further trenching wheel axis 8 B is in the vertical direction adjustable relative to the base frame 6 .
- FIG. 10 shows a side view of a sixth embodiment of the trenching device and method.
- the trenching device 1 differs from the one shown in FIG. 8 , in that the radius R 1 A of the trenching wheel 7 A is smaller than the radius R 1 B of the further trenching wheel 7 B.
- FIGS. 11 and 12 show a top view of a third embodiment of the trenching device 1 and method.
- the ballast 9 is not shown in order to obtain a clear view.
- the trenching device 1 can be provided with the ballast 9 shown in FIG. 1 .
- the base frame 6 comprises a first frame part 25 and a second frame part 26 which are connected to each other via a pivot connection 27 , the trenching wheel 7 is connected to the first frame part 25 , and a propulsion unit 11 B is connected to the second frame part 26 .
- the second frame part 26 is pivotable about a frame pivot axis 28 relative to the first frame part 25 , and the frame axis extends perpendicular to the trenching wheel axis 8 .
- the trenching device 1 comprises a steering system 29 configured to pivot the second frame part 26 relative to the first frame part 25 .
- the steering system 29 is formed by two steering actuator 44 positioned at opposite sides of the pivot connection 27 .
- Each steering actuator 44 is connected with one end to the first frame part 25 and with the other end to the second frame part 26 .
- the length of the steering actuators can be increased or decreased.
- the first frame part 25 and second frame part 26 are positioned in line with each other.
- straight trench 2 is formed when the trenching device 1 is moved along the seabed 3 .
- the length of one of the steering actuators for example the first steering actuator 41
- the length of the other steering actuator in said situation the second steering actuator 42
- the first and second frame part 26 will pivot relative to each other as shown in FIG. 8 .
- a curved trench 2 is formed when the trenching device 1 is moved along the seabed 3 .
- the operations of the propulsion system (formed by the propulsion units 11 A, 11 B), ballast system (not shown), and steering system 29 (formed by the steering actuators 41 , 42 ) are controlled by the control system 45 provided on the base frame 6 .
- the method of forming the trench 2 in the seabed 3 comprises pivoting the second frame part 26 relative to the first frame part 25 to adjust the direction in which the trenching device 1 is moved along the seabed 3 .
- FIG. 13 shows a side view of a fourth embodiment of the trenching device 1 and method.
- FIG. 14 shows a view in cross section along line X-X of the trenching device 1 of FIG. 9 .
- the base frame 6 comprises a first frame side 30 and an opposite second frame side 31 and supports 32 are connected to the first frame side 30 and second frame side 31 to hold the trenching wheel 7 in an upwardly extending position.
- the trenching device 1 has in total four supports 32 .
- the supports 32 are constructed to be positioned in contact with the seabed 3 .
- Each least support is provided with at least one propulsion unit 11 C-F.
- Each of said propulsion units 11 C-F comprise a driven a caterpillar track.
- the supports 32 comprise support actuators 44 .
- the supports actuators 44 are constructed to adjust the height H 1 , H 2 of the supports 32 . This way the supports 32 can follow unevenness of the seabed 3 .
- the trenching device 1 is configured to cope with gouges of around 2 m in the seabed 3 and berms of around 2 m on the seabed 3 .
- the operations of the propulsion system formed by the propulsion units 11 A, 11 B and 11 C-F), ballast system 15 (comprising the pump system 17 ) and support actuators 32 are controlled by the control system 45 provided on the base frame 6 .
- FIG. 15 schematically shows a side view of a fifth embodiment of the trenching device 1 and method.
- the trenching device 1 differs from the one shown in FIGS. 9 and 10 in that the propulsion unit 11 B formed by the assisting wheel 23 is removed and replaced by a propulsion unit 11 B comprising a driven caterpillar track 43 connected to the base frame 6 .
- the operations of the propulsion system formed by the propulsion units 11 A, 11 B and 11 C-F), ballast system 15 (comprising the pump system 17 ) and support actuators 32 are controlled by the control system 45 provided on the base frame 6 .
Abstract
A trenching device (1) for forming a trench (2) in a seabed (3) to receive an elongate object, such as a pipeline, said trenching device (1) comprising a base frame (6), and a trenching wheel (7) which is connected to the base frame (6) and rotatable about a trenching wheel axis (8) to form the trench (2), wherein the trenching device (1) is configured to push the trenching wheel (7) into the seabed (3) when the trenching wheel (7) is positioned on the seabed (3).
Description
- The invention relates to the forming of a trench in a seabed to receive an elongate object, such as a pipeline.
- Shallow Arctic waters are characterized by the occurrence of ice ridges which may hit the seabed in typical water depths between 10 and 60 meters and form deep gouges into the soil. Pipelines crossing such ice ridge zones must be buried deeply below the seabed to avoid damage as a result of ice ridge loading. Typical burial depths against ice ridges are 4 to 6 meters.
- In other Arctic waters, icebergs may occur. Icebergs are heavier than ice ridges and may have a draft of 200 to 300 meters. Icebergs may touch the seabed in water depths as deep as 200 to 300 meters and form even deeper gouges than ice ridges. Typical pipeline burial depths against ice bergs may be as deep as 5 to 8 meters.
- For protection against ice ridge or iceberg loading, the trench must be backfilled after the pipeline has been laid in it.
- The seabed in Arctic offshore regions frequently contain hard glacial over-consolidated soils with frequent occurrence of boulders. Occasionally, lenses of permafrost may occur. The hard soils may be covered by a few meters of soft Holocene soils. The surface of the seabed is very uneven as a result of gouges and berms formed in the past. Gouges may be as deep as 2 to 4 meters below the average seabed and berms as high as 2 meters above it. The gouges may be filled with loose sands and silts.
- An additional requirement is, that the offshore installation season in the Arctic may be extremely short, i.e. as short as 1 and 2 months per year. In that limited time typical pipeline lengths of 100 to 200 kilometres must be laid, buried and backfilled before the sea freezes up again and new ice ridges are formed. It will be clear that the same situations arise in the Antarctic waters.
- Existing trenching technologies are ploughing, excavating, jetting and suction cutting. Each of these technologies has one or more drawbacks, such as that it is not suitable for deep trenches as required in Arctic soil condition, does not comply with requirements for environmental conditions (for example due to the forming of dust clouds in the water or removal of too much soil), or has difficulties with hard objects such as big stones, boulders, or frozen soil.
- It is an object to provide an improved, or at least alternative, solution for the forming of a trench in a seabed to burry an elongate pipe, such as a pipeline.
- This object is achieved with a trenching device for forming a trench in a seabed to receive an elongate object, such as a pipeline, said trenching device comprising a base frame, and a trenching wheel which is connected to the base frame and rotatable about a trenching wheel axis to form the trench, wherein the trenching device is configured to push the trenching wheel into the seabed when the trenching wheel is positioned on the seabed. This allows the forming of a trench without the need of ploughing, excavating, jetting or suction cutting.
- In an embodiment of the trenching device, the trenching device is configured to push the soil of the seabed away with the trenching wheel to form the trench, without conveying excavated soil of the seabed out of the trench
- In an embodiment of the trenching device, the trenching device is configured to form the trench by only pushing the soil of the seabed away with the rotating trenching wheel when the trenching device is moved along the seabed.
- In an embodiment of the trenching device, the trenching wheel rotates in the direction of movement of the trenching device.
- In an embodiment of the trenching device, a ballast is provided to push the trenching wheel into the seabed when the trenching wheel is positioned on the seabed.
- In an embodiment of the trenching device, the trenching wheel is configured and arranged to push the soil of the seabed to the side when the trenching device is moved along the seabed while the trenching wheel is pushed into the seabed.
- In an embodiment of the trenching device, the trenching wheel comprises an outer circumference.
- In an embodiment of the trenching device, the trenching wheel comprises a first side surface and an opposite second side surface, the trenching wheel is arranged such that the outer circumference is pushed into the seabed and the first side surface and second side surface push the soil of the seabed to the side when the trenching device is moved along the seabed.
- In an embodiment of the trenching device, the trenching wheel comprises a radius R1 which is larger than a depth D of the trench that is formed.
- In an embodiment of the trenching device, the radius R1 is between 5 and 15 m.
- In an embodiment of the trenching device, the radius R1 is between 10 and 12 m.
- In an embodiment of the trenching device, the trenching device is configured to form a trench with a depth D between 1 and 8 m.
- In an embodiment of the trenching device, the trenching device is configured to form a trench with a depth D of around 5 m.
- In an embodiment of the trenching device, the trenching wheel axis in use extends parallel, or substantially parallel, to the seabed.
- In an embodiment of the trenching device, the trenching wheel extends perpendicular from the base frame.
- In an embodiment of the trenching device, the trenching wheel in use extends upwardly from the seabed.
- In an embodiment of the trenching device, the outer circumference of the trenching wheel is rounded.
- In an embodiment of the trenching device, the outer circumference of the trenching wheel is roughened to enhance friction between said outer circumference and the seabed.
- In an embodiment of the trenching device, the trenching wheel, in the direction of the trenching wheel axis, comprises a thickness and the thickness decreases in the direction from the trenching wheel axis to the outer circumference of the trenching wheel.
- In an embodiment of the trenching device, the trenching wheel comprises a thickness t1 near the trenching wheel axis and a thickness t2 near the outer circumference of the trenching wheel, and the thickness decreases in the direction from the trenching wheel axis to the outer circumference of the trenching wheel.
- In an embodiment of the trenching device, the trenching wheel comprises a thickness t1 near the trenching wheel axis and a thickness t2 near the outer circumference of the trenching wheel, and the thickness decreases in the direction from the trenching wheel axis to the outer circumference of the trenching wheel in a linear manner from t1 to t2.
- In an embodiment of the trenching device, t1 is between 1.5 and 4 m and t2 is between 1 and 2 m.
- In an embodiment of the trenching device, the ballast is formed, or partly formed, by a fixed ballast member connected to the base frame in a fixed position.
- In an embodiment of the trenching device, the ballast is formed, or partly formed, by a ballast system.
- In an embodiment of the trenching device, the ballast system is configured to adjust the magnitude of the force working on the base frame.
- In an embodiment of the trenching device, the ballast system is configured to adjust the position of the force working on the base frame.
- In an embodiment of the trenching device, the ballast system comprises a ballast tank configured to hold a fluid.
- In an embodiment of the trenching device, the ballast tank comprises multiple ballast compartments.
- In an embodiment of the trenching device, the ballast system comprises a pump system to pump water and gas in the ballast tank.
- In an embodiment of the trenching device, the pump system is configured to pump water and gas in multiple ballast compartments independently from each other.
- In an embodiment of the trenching device, the ballast is formed, or partly formed, by the mass of the trenching wheel.
- In an embodiment of the trenching device, wherein the trenching wheel at the inside thereof is filled with a material to enhance the mass of the trenching wheel.
- In an embodiment of the trenching device, the majority of the ballast is located above the trenching wheel axis.
- In an embodiment of the trenching device, the trenching device comprises a front side and a rear side, the trenching device is configured to be moved in the direction from the rear side to the front side, the resultant force of the ballast acting on the base frame is located at a distance e beyond the trenching wheel axis when seen in the direction from the rear side to the front side.
- In an embodiment of the trenching device, the trenching device comprises a propulsion system formed by at least one propulsion unit which is connected to the base frame to move the trenching device along the seabed.
- In an embodiment of the trenching device, at least one propulsion unit comprises a wheel drive to rotate the trenching wheel around the trenching wheel axis in order to move the trenching device along the seabed.
- In an embodiment of the trenching device, the base frame comprises a connector to connect the base frame to an external propulsion system for moving the trenching device along the seabed.
- In an embodiment of the trenching device, the base frame comprises a length direction, and at least one propulsion unit is connected to the base frame at a distance from the trenching wheel in said length direction.
- In an embodiment of the trenching device, at least one propulsion unit comprises an assisting wheel connected to the base frame and rotatable about an assisting wheel axis, and a further wheel drive to rotate the assisting wheel around the assisting wheel axis in order to move the trenching device along the seabed.
- In an embodiment of the trenching device, the trenching wheel axis and the assisting wheel axis extend in one plane.
- In an embodiment of the trenching device, at least one propulsion unit comprises a driven caterpillar track.
- In an embodiment of the trenching device, the trenching wheel axis and the assisting wheel axis extend parallel, or substantially parallel, to each other.
- In an embodiment of the trenching device, the assisting wheel axis in use extends parallel, or substantially parallel, to the seabed.
- In an embodiment of the trenching device, the assisting wheel comprises an outer circumference.
- In an embodiment of the trenching device, the outer circumference of the assisting wheel is rounded.
- In an embodiment of the trenching device, the outer circumference of the assisting wheel is roughened to enhance friction between said outer circumference and the seabed.
- In an embodiment of the trenching device, the assisting wheel in the direction of the assisting wheel axis comprises a thickness t3 and the thickness t3 remains constant in the direction from the assisting wheel axis to the outer circumference of the assisting wheel.
- In an embodiment of the trenching device, the thickness t3 equals t2.
- In an embodiment of the trenching device, the thickness t3 is larger than t2 and smaller than t1.
- In an embodiment of the trenching device, the thickness t3 is larger than t2 and smaller than t2+0.5(t1−t2).
- In an embodiment of the trenching device, the assisting wheel comprises a radius R2 which equals R1.
- In an embodiment of the trenching device, the base frame comprises a first frame part and a second frame part which are connected to each other via a pivot connection, the trenching wheel is connected to the first frame part, and at least one propulsion unit is connected to the second frame part.
- In an embodiment of the trenching device, the second frame part is pivotable about a frame pivot axis relative to the first frame part, and the frame pivot axis extends perpendicular, or substantially perpendicular, to the trenching wheel axis.
- In an embodiment of the trenching device, the trenching device comprises a steering system configured to pivot the second frame part relative to the first frame part.
- In an embodiment of the trenching device, the base frame comprises a first frame side and an opposite second frame side and supports are connected to the first frame side and second frame side to hold the trenching wheel in an upwardly extending position.
- In an embodiment of the trenching device, the supports are constructed to be positioned in contact with the seabed.
- In an embodiment of the trenching device, at least one of the supports is provided with at least one propulsion unit.
- In an embodiment of the trenching device, the height of the supports is adjustable to follow unevenness of the seabed.
- In an embodiment of the trenching device, the trenching device comprises a further trenching wheel which is connected to the base frame and rotatable about a further trenching wheel axis to form the trench, and the trenching device is configured to push the further trenching wheel into the seabed when the further trenching wheel is positioned on the seabed.
- In an embodiment of the trenching device, the trenching device comprises a further ballast to push the further trenching wheel into the seabed when the further trenching wheel is positioned on the seabed.
- In an embodiment of the trenching device, the further trenching wheel comprises corresponding features of the trenching wheel as defined in any of the claims 3-12.
- In an embodiment of the trenching device, the further ballast comprises corresponding features of the ballast as defined in any of the claims 13-23.
- In an embodiment of the trenching device, the trenching device is configured to push the trenching wheel over a first distance D1 into the seabed and to push the further trenching wheel over a second distance D2 into the seabed.
- In an embodiment of the trenching device, the distance D2 is larger than the distance D1.
- The invention further relates to a method of forming a trench in a seabed to receive an elongate object, such as a pipeline, with a trenching device comprising a base frame, a trenching wheel which is connected to the base frame and rotatable about a trenching wheel axis to form the trench, wherein the trenching device is configured to push the trenching wheel into the seabed when the trenching wheel is positioned on the seabed and said method comprises positioning the trenching wheel on the seabed, pushing the trenching wheel into the seabed, and moving the trenching device along the seabed to form the trench.
- In an embodiment of the method, the method comprises pushing the soil of the seabed away with the trenching wheel to form the trench, without conveying excavated soil out of the trench.
- In an embodiment of the method, the method comprises forming the trench by only pushing the soil of the seabed away with the rotating trenching wheel when the trenching device is moved along the seabed.
- In an embodiment of the method, the method comprises rotating the trenching wheel in the direction of movement of the trenching device.
- In an embodiment of the method, the trenching device comprises a ballast and the method comprises pushing the trenching wheel into the seabed by the weight of the ballast.
- In an embodiment of the method, the method comprises pushing the soil of the seabed to the side by moving the trenching device along the seabed while the trenching wheel is pushed into the seabed.
- In an embodiment of the method, the trenching wheel comprises an outer circumference, a first side surface and an opposite second side surface, the method comprises pushing the outer circumference into the seabed and pushing the soil of the seabed to the side with the first side surface and the second side surface by moving the trenching device is along the seabed.
- In an embodiment of the method, the trenching device comprises a front side and a rear side and the method comprises moving the trenching device in the direction from the rear side to the front side.
- In an embodiment of the method, the ballast is formed, or partly formed, by a ballast system configured to adjust the magnitude and/or the position of the force of the ballast working on the base frame, and the method comprises adjusting the magnitude and/or the position of the force of the ballast working on the base frame to push the trenching wheel into the seabed.
- In an embodiment of the method, the ballast system comprises a ballast tank configured to hold a fluid and the method comprises filling the ballast tank with water to increase the magnitude of the force of the ballast working on the base frame. This means that the ballast tank can be partly filled or completely filled with water. The ballast tank can be filled between 0 and 100% with water, depending on the required force of the ballast.
- In an embodiment of the method, wherein the method comprises filling the ballast tank with air to decrease the magnitude of the force of the ballast working on the base frame and/or to create buoyancy such that the trenching device is neutrally buoyant or floats up in the water. This means that the ballast tank can be partly filled or completely filled with gas. The ballast tank can be filled between 0 and 100% with gas.
- In an embodiment of the method, the trenching device comprises a propulsion system formed by at least one propulsion unit connected to the base frame and the method comprise moving the trenching device along the seabed with the propulsion system.
- In an embodiment of the method, at least one propulsion unit comprises a wheel drive to rotate the trenching wheel around the trenching wheel axis and the method comprises rotating the trenching wheel to move the trenching device along the seabed.
- In an embodiment of the method, the base frame comprises a length direction, and at least one propulsion unit is connected to the base frame at a distance from the trenching wheel in said length direction and the method comprises moving the trenching device along seabed with the propulsion unit.
- In an embodiment of the method, at least one propulsion unit comprises an assisting wheel connected to the base frame and rotatable about an assisting wheel axis and a further wheel drive to rotate the assisting wheel around the assisting wheel axis and the method comprise rotating the assisting wheel around the assisting wheel axis to move the trenching device along the seabed.
- In an embodiment of the method, the base frame comprises a first frame part and a second frame part which are connected to each other via a pivot connection, the trenching wheel is connected to the first frame part, at least one propulsion unit is connected to the second frame part, the trenching device comprises a steering system configured to pivot the second frame part relative to the first frame part and the method comprises pivoting the second frame part relative to the first frame part to adjust the direction in which the trenching device is moved along the seabed.
- In an embodiment of the method, the trenching device comprises a further trenching wheel which is connected to the base frame and rotatable about a further trenching wheel axis to form the trench, and the trenching device is configured to push the further trenching wheel into the seabed when the further trenching wheel is positioned on the seabed and the method comprises pushing the trenching wheel over a first distance D1 into the seabed and pushing the further trenching wheel over a second distance D2 into the seabed, while the trenching device is moved along the seabed.
- In an embodiment of the method, the distance D2 is larger than the distance D1.
- The invention further relates to a method of forming a trench in a seabed to receive an elongate object, such as a pipeline, with the trenching device according to the invention, wherein said method comprises positioning the trenching wheel on the seabed, pushing the trenching wheel into the seabed, and moving the trenching device along the seabed to form the trench. In an embodiment, said method comprises the method steps defined in any of the claims 45-59.
- The invention further relates to a use of the trenching device according to the invention to form a trench in a seabed.
- Embodiments of the trenching device and the method will be described by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:
-
FIG. 1 schematically shows a side view of a first embodiment of the trenching device and method, -
FIG. 2 schematically shows a view in cross section along line II-II of the trenching device ofFIG. 1 , -
FIG. 3 schematically shows a side view of the trenching wheel ofFIG. 1 , -
FIG. 4 schematically shows a side view a second embodiment of the trenching device and method, -
FIG. 5 schematically shows a view in cross section along line V-V of the trenching device ofFIG. 4 , -
FIG. 6 schematically shows a side view of the trenching wheel ofFIG. 4 , -
FIG. 7 schematically shows a side view of a third embodiment of the trenching device and method, -
FIG. 8 schematically shows a side view of a fourth embodiment of the trenching device and method, -
FIG. 9 schematically shows a side view of a fifth embodiment of the trenching device and method, -
FIG. 10 schematically shows a side view of a sixth embodiment of the trenching device and method, -
FIGS. 11 and 12 schematically show a top view of a seventh embodiment of the trenching device and method, -
FIG. 13 schematically shows a side view of a eight embodiment of the trenching device and method, -
FIG. 14 schematically shows a view in cross section along line X-X of the trenching device ofFIG. 13 , and -
FIG. 15 schematically shows a side view of a ninth embodiment of the trenching device and method. - The
FIG. 1 shows a side view of a first embodiment of the trenching device and method. Thetrenching device 1 is forming atrench 2 in aseabed 3 to receive an elongate object, such as a pipeline. Thetrenching device 1 comprises abase frame 6, and atrenching wheel 7 which is connected to thebase frame 6 and rotatable about atrenching wheel axis 8 to form thetrench 2. Thetrenching device 1 is configured to push thetrenching wheel 7 into theseabed 3 when thetrenching wheel 7 is positioned on theseabed 3. This means that the trench is formed without ploughing, excavating, jetting or suction cutting. - The
trenching device 1 is configured to push the soil of theseabed 3 away with thetrenching wheel 7 to form thetrench 2, without conveying excavated soil of theseabed 3 out of thetrench 2. - The
trenching device 1 is configured to form thetrench 2 by only pushing the soil of theseabed 3 away with therotating trenching wheel 7 when thetrenching device 1 is moved along theseabed 3. When thetrenching device 1 is moved along theseabed 3, thetrenching wheel 7 is rotated in the direction of movement of thetrenching device 1. The rotation of thetrenching wheel 7 is indicated byarrow 24. - A
ballast 9 is provided to push thetrenching wheel 7 into theseabed 3 when thetrenching wheel 7 is positioned on theseabed 3. Thetrenching wheel 7 is configured and arranged to push the soil of theseabed 3 to the side when thetrenching device 1 is moved along theseabed 3 while thetrenching wheel 7 is pushed into theseabed 3 by theballast 9. Thetrenching wheel 7 comprises anouter circumference 13. Thetrenching wheel 7 comprises a first side surface 4 and an oppositesecond side surface 5, thetrenching wheel 7 is arranged such that theballast 9 pushes theouter circumference 13 into theseabed 3 and the first side surface 4 andsecond side surface 5 push the soil of theseabed 3 to the side when thetrenching device 1 is moved along theseabed 3. Thetrenching device 1 comprises afront side 18 and arear side 19. Thetrenching device 1 is moved in the direction from therear side 19 to thefront side 18, as indicated byarrow 20. - The
trenching wheel 7 comprises a radius R1 which is larger than a depth D of thetrench 2 that is formed. The radius R1 is around 10 m. In other examples of thetrenching device 1, the radius R1 is between 5 and 15 m. The depth D of thetrench 2 is around 5 m. In other examples thetrenching device 1 is configured to form a trench with a depth D between 1 and 8 m. - The
trenching wheel axis 8 extends parallel, or substantially parallel, to theseabed 3. Thetrenching wheel 7 extends perpendicular from thebase frame 6. Thetrenching wheel 7 extends upwardly from theseabed 3. - The
ballast 9 is formed by a fixedballast member 14 connected to thebase frame 6 in a fixed position and by aballast system 15. Theballast system 15 is configured to adjust the magnitude and the position of the force working on thebase frame 6. This means that the amount of Newton theballast system 15 subjects to thebase frame 6 can be controlled. Also the position where the force of theballast system 15 is subjected onbase frame 6 can be controlled. In other examples of thetrenching device 1, only the magnitude or the position of the force of theballast system 15 working on thebase frame 6 can be adjusted. - The
ballast system 15 comprises aballast tank 16 configured to hold a fluid. Theballast tank 16 can hold liquid and gas. Theballast tank 16 comprises multiple ballast compartments 34. Theballast system 15 comprises apump system 17 to pump either water and gas in theballast tank 16. Thepump system 17 is configured to pump water and gas in themultiple ballast compartments 34 independently from each other. Eachballast compartment 34 can be filled between 0 and 100% with water, independently from each other. Eachballast compartment 34 can be filled between 0 and 100% with gas, independently from each other. The ballast compartments 34 are positioned next to each other along thebase frame 6. By controlling the amount of water held by theballast tank 16, the magnitude of the force of theballast system 15 can be adjusted. By controlling the amount of water in thedifferent ballast compartments 34, the position where the force of theballast system 15 works on thebase frame 6 can be adjusted. - In the situation shown, the majority of the
ballast 9 is located beyond thetrenching wheel axis 8 when seen in the direction from therear side 19 to thefront side 18. The resultant force Fr of theballast 9 acting on thebase frame 6 is located beyond thetrenching wheel axis 8 when seen in the direction from therear side 19 to thefront side 18. The resultant force Fr of theballast 9 acting on thebase frame 6 is located at a distance e beyond thetrenching wheel axis 8 when seen in the direction from therear side 19 to thefront side 18. By adding water or gas in thedifferent ballast compartments 34, theballast system 15 can adjust the distance e. - The
ballast 9 is located above thetrenching wheel axis 8. In other examples of thetrenching device 1, the majority of theballast 9 is located above thetrenching wheel axis 8. In other examples of thetrenching device 1, theballast 9 is formed, or partly formed, by the mass of thetrenching wheel 7. In said situation, thetrenching wheel 7 is constructed to have a large mass. The inside of thetrenching wheel 7 can for example be filled with a material, such a concrete, to enhance the mass of thetrenching wheel 7. - The
trenching device 1 comprises a propulsion system formed by a propulsion unit 11 which is connected to thebase frame 6 to move thetrenching device 1 along theseabed 3. The propulsion unit 11 comprises awheel drive 10 to rotate thetrenching wheel 7 around thetrenching wheel axis 8 in order to move thetrenching device 1 along theseabed 3. Thebase frame 6 comprises aconnector 21 to connect thebase frame 6 to anexternal propulsion system 12, such as a vessel, for moving thetrenching device 1 along theseabed 3. In other examples of thetrenching device 1, only aconnector 21 and no propulsion system is provided. In other examples of thetrenching device 1, the propulsion system comprises multiple propulsion units. - The operations of the propulsion system (formed by the propulsion unit 11) and ballast system 15 (comprising the pump system 17) are controlled by a
control system 45 provided on thebase frame 6. -
FIG. 2 shows a view in cross section along line II-II of thetrenching device 1. Thetrenching wheel 7 comprises anouter circumference 13. Theouter circumference 13 forms a transition from the first side surface 4 and thesecond side surface 5. Theouter circumference 13 of thetrenching wheel 7 is rounded. Theouter circumference 13 is rounded in the direction from the first side surface 4 to thesecond side surface 5. The roundedouter circumference 13 increases the surface area of theouter circumference 13 and therefore enhances the friction between theouter circumference 13 and the soil of theseabed 3 when thetrenching wheel 7 is driven around thetrenching wheel axis 8. Theouter circumference 13 of thetrenching wheel 7 is roughened to enhance the friction between saidouter circumference 13 and theseabed 3. - In the direction of the
trenching wheel axis 8, thetrenching wheel 7 comprises a thickness and the thickness decreases in the direction from thetrenching wheel axis 8 to theouter circumference 13 of thetrenching wheel 7. Said form of thetrenching wheel 7 facilitates the forming of the trench. Thetrenching wheel 7 comprises a thickness t1 near thetrenching wheel axis 8 and a thickness t2 near theouter circumference 13 of thetrenching wheel 7. The thickness decreases in the direction from thetrenching wheel axis 8 to theouter circumference 13 of thetrenching wheel 7. The thickness decreases in a linear manner from t1 to t2. The thickness t1 is around 3 m and t2 is around 1.5 m. In other examples of thetrenching device 1, the thickness decreases in a non-linear manner from t1 to t2. In other examples of thetrenching device 1, the thickness t1 is between 1.5 and 4 m and t2 is between 1 and 2 m. The bottom of thetrench 2 has a width of at least 1 m. - The method of forming the
trench 2 in theseabed 3 to receive an elongate object, such as a pipeline, with thetrenching device 1 comprises positioning thetrenching wheel 7 on theseabed 3, pushing thetrenching wheel 7 into theseabed 3 by the weight of theballast 9, moving thetrenching device 1 along theseabed 3 to form the trench. The soil of theseabed 3 is pushed to the side by moving thetrenching device 1 along theseabed 3 while thetrenching wheel 7 is pushed into theseabed 3 by theballast 9. Theouter circumference 13 of thetrenching wheel 7 is pushed into theseabed 3 by theballast 9 and the soil of theseabed 3 is pushed to the side with the first side surface 4 and thesecond side surface 5 by moving thetrenching device 1 is along theseabed 3. Thetrenching device 1 is moved in the direction from therear side 19 to thefront side 18. Thetrenching device 1 is moved along theseabed 3 with the propulsion system. Thetrenching wheel 7 is rotated to move thetrenching device 1 along theseabed 3. - The magnitude and the position of the force of the
ballast 9 working on thebase frame 6 to push totrenching wheel 7 into theseabed 3 can be adjusted. Theballast tank 16 can be filled with water to increase the magnitude of the force of theballast 9 working on thebase frame 6. Theballast tank 16 can be filled between 0 and 100% with water, depending on the required force of theballast 9. Theballast tank 16 can be filled with air to decrease the magnitude of the force of theballast 9 working on thebase frame 6. This way, the magnitude of the force can be adjusted to the hardness of the soil in which thetrench 2 is formed. Harder soils require a large force, whereas softer soil require a smaller force. Theballast tank 16 can be filled with air to create buoyancy such that thetrenching device 1 is neutrally buoyant or floats up in the water. Theballast system 15 is configured position thetrenching device 1 in a horizontal, or substantially horizontal, position when floating at the water surface or under the water surface. Theballast tank 16 can be filled between 0 and 100% with gas. -
FIG. 3 shows a side view of thetrenching wheel 7 ofFIG. 1 being moved in thedirection 20 along theseabed 3 while being pushed into theseabed 3 by theballast 9. Due to the form of thetrenching wheel 7, only a relatively small part first side surface 4 andsecond side surface 5 of thetrenching wheel 7 will be in contact with the soil of theseabed 3. Only the indicatedfriction area 37 of thetrenching wheel 7 will be in contact with the soil of theseabed 3. This tends to have a positive effect on the friction of the soil of theseabed 3 which thetrenching device 1 experiences when forming the trench. -
FIG. 4 shows a side view a second embodiment of thetrenching device 1 and method. Thetrenching device 1 ofFIG. 4 differs from the one inFIG. 1 in that it does not comprises aconnector 21 and in that anadditional propulsion unit 11B formed by an assistingwheel 23 is provided. In other examples of thetrenching device 1, aconnector 21 can be provided in combination with the assistingwheel 23 or a different type ofadditional propulsion unit 11B. In other examples of thetrenching device 1, the propulsion system only comprises the driven assistingwheel 23. - The
base frame 6 comprises alength direction 22, and theadditional propulsion unit 11B is connected to thebase frame 6 at a distance from thetrenching wheel 7 in saidlength direction 22. The additional propulsion unit 11 comprises an assistingwheel 23 connected to thebase frame 6 and rotatable about an assistingwheel axis 33, and a further wheel drive 10B to rotate the assistingwheel 23 around the assistingwheel axis 33 in order to move thetrenching device 1 along theseabed 3. When thetrenching device 1 is moved along theseabed 3, thetrenching wheel 7 and the assistingwheel 23 rotate in the direction of thearrows - The
trenching wheel axis 8 and the assistingwheel axis 33 extend in one plane. Thetrenching wheel axis 8 and the assistingwheel axis 33 extend parallel to each other. The assistingwheel axis 33 extends parallel, or substantially parallel, to theseabed 3. The assistingwheel 23 extends perpendicular from thebase frame 6. The assistingwheel 23 in use extends upwardly from theseabed 3. - The operations of the propulsion system (formed by the
propulsion units control system 45 provided on thebase frame 6. -
FIG. 5 shows a view in cross section along line V-V of thetrenching device 1 ofFIG. 4 . The assistingwheel 23 comprises anouter circumference 35, afirst side surface 39 and asecond side surface 40. Theouter circumference 35 of the assistingwheel 23 is rounded. Theouter circumference 35 of the assistingwheel 23 is rounded in a similar manner as theouter circumference 13 of thetrenching wheel 7 is rounded. Theouter circumference 35 of the assistingwheel 23 is roughened to enhance friction between saidouter circumference 35 and the soil of theseabed 3. In the direction of the assistingwheel axis 33, the assistingwheel 23 comprises a thickness t3 and the thickness t3 remains constant in the direction from the assistingwheel axis 33 to theouter circumference 35 of the assistingwheel 23. The thickness t3 is around 1.5 In other examples of thetrenching device 1, the thickness t3 is larger than t2 and smaller than t2+0.5(t1−t2). The assistingwheel 23 comprises a radius R2 which equals R1. In other examples of thetrenching device 1, the assistingwheel 23 comprises a radius R2 which differs from R1. -
FIG. 6 shows a side view of thetrenching wheel 7 ofFIG. 4 being moved through the trench. Due to the form of the assistingwheel 23, only a relatively small part of thefirst side surface 39 andsecond side surface 40 of the assistingwheel 23 will be in contact with the soil of theseabed 3. Only the indicatedfriction area 38 of the assistingwheel 23 will be in contact with the soil of theseabed 3. This tends to have a positive effect on the friction of the soil of theseabed 3 which thetrenching device 1 experiences when forming the trench. Thetrenching device 1 is configured to form a trench with a length of around 10 km a day. - The method of forming the
trench 2 in theseabed 3 comprises rotating the assistingwheel 23 around the assistingwheel axis 33 to move thetrenching device 1 along theseabed 3. -
FIG. 7 shows a side view of a third embodiment of the trenching device and method. Thetrenching device 1 differs from the one shown inFIG. 4 , in that afurther ballast 9B is provided at the assistingwheel 23. Thefurther ballast 9B comprises two fixedfurther ballast members 14B and afurther ballast system 15B. Thefurther ballast system 15B has the same or corresponding design as theballast system 15A. Thefurther ballast 9B allows to enhance the grip that the assistingwheel 23 has on the soil of theseabed 3. The operations of thefurther ballast system 15B is also controlled by thecontrol system 45. -
FIG. 8 shows a side view of a fourth embodiment of the trenching device and method. Thetrenching device 1 comprises afurther trenching wheel 7B which is connected to thebase frame 6 and rotatable about a furthertrenching wheel axis 8B to form thetrench 2, and thetrenching device 1 is configured to push thefurther trenching wheel 7B into theseabed 3 when thefurther trenching wheel 7B is positioned on theseabed 3. - The
trenching device 1 comprises afurther ballast 9B to push thefurther trenching wheel 7B into theseabed 3 when thefurther trenching wheel 7B is positioned on theseabed 3. Thefurther trenching wheel 7B has the same or corresponding design as thetrenching wheel 7A. Thefurther ballast system 15B has the same or corresponding design as theballast system 15A. Thetrenching device 1 is configured to push thetrenching wheel 7A over a first distance D1 into the seabed and to push thefurther trenching wheel 7B over a second distance D2 into the seabed. The distance D2 is larger than the distance D1. - The method of forming a trench comprises pushing the
trenching wheel 7A over a first distance D1 into the seabed and pushing thefurther trenching wheel 7B over a second distance D2 into the seabed, while thetrenching device 1 is moved along theseabed 3. - In other examples, the
trenching device 1 comprisesmultiple trenching wheels 7 in combination with one or more assistingwheels 23. -
FIG. 9 shows a side view of a fifth embodiment of the trenching device and method. Thetrenching device 1 differs from the one shown inFIG. 8 , in thattrenching wheel axis 8A is positioned higher in the vertical direction relative to the furthertrenching wheel axis 8B. The trenching device is configured to adjust the position of thetrenching wheel axis 8A in the vertical direction relative to thebase frame 6. In other examples, the position of the furthertrenching wheel axis 8B is in the vertical direction also adjustable relative to thebase frame 6. In other examples, only the position of the furthertrenching wheel axis 8B is in the vertical direction adjustable relative to thebase frame 6. -
FIG. 10 shows a side view of a sixth embodiment of the trenching device and method. Thetrenching device 1 differs from the one shown inFIG. 8 , in that the radius R1A of thetrenching wheel 7A is smaller than the radius R1B of thefurther trenching wheel 7B. -
FIGS. 11 and 12 show a top view of a third embodiment of thetrenching device 1 and method. Theballast 9 is not shown in order to obtain a clear view. Thetrenching device 1 can be provided with theballast 9 shown inFIG. 1 . - The
base frame 6 comprises afirst frame part 25 and asecond frame part 26 which are connected to each other via apivot connection 27, thetrenching wheel 7 is connected to thefirst frame part 25, and apropulsion unit 11B is connected to thesecond frame part 26. Thesecond frame part 26 is pivotable about aframe pivot axis 28 relative to thefirst frame part 25, and the frame axis extends perpendicular to thetrenching wheel axis 8. Thetrenching device 1 comprises asteering system 29 configured to pivot thesecond frame part 26 relative to thefirst frame part 25. Thesteering system 29 is formed by two steeringactuator 44 positioned at opposite sides of thepivot connection 27. Each steeringactuator 44 is connected with one end to thefirst frame part 25 and with the other end to thesecond frame part 26. The length of the steering actuators can be increased or decreased. InFIG. 7 , thefirst frame part 25 andsecond frame part 26 are positioned in line with each other. As a result of this, asstraight trench 2 is formed when thetrenching device 1 is moved along theseabed 3. When the length of one of the steering actuators (for example the first steering actuator 41) is decreased and the length of the other steering actuator (in said situation the second steering actuator 42) is increased, the first andsecond frame part 26 will pivot relative to each other as shown inFIG. 8 . As result of this, acurved trench 2 is formed when thetrenching device 1 is moved along theseabed 3. - The operations of the propulsion system (formed by the
propulsion units actuators 41, 42) are controlled by thecontrol system 45 provided on thebase frame 6. - The method of forming the
trench 2 in theseabed 3 comprises pivoting thesecond frame part 26 relative to thefirst frame part 25 to adjust the direction in which thetrenching device 1 is moved along theseabed 3. -
FIG. 13 shows a side view of a fourth embodiment of thetrenching device 1 and method.FIG. 14 shows a view in cross section along line X-X of thetrenching device 1 ofFIG. 9 . Thebase frame 6 comprises afirst frame side 30 and an oppositesecond frame side 31 and supports 32 are connected to thefirst frame side 30 andsecond frame side 31 to hold thetrenching wheel 7 in an upwardly extending position. Thetrenching device 1 has in total four supports 32. The supports 32 are constructed to be positioned in contact with theseabed 3. Each least support is provided with at least onepropulsion unit 11C-F. Each of saidpropulsion units 11C-F comprise a driven a caterpillar track. The supports 32comprise support actuators 44. The supports actuators 44 are constructed to adjust the height H1, H2 of thesupports 32. This way thesupports 32 can follow unevenness of theseabed 3. Thetrenching device 1 is configured to cope with gouges of around 2 m in theseabed 3 and berms of around 2 m on theseabed 3. The operations of the propulsion system (formed by thepropulsion units support actuators 32 are controlled by thecontrol system 45 provided on thebase frame 6. -
FIG. 15 schematically shows a side view of a fifth embodiment of thetrenching device 1 and method. Thetrenching device 1 differs from the one shown inFIGS. 9 and 10 in that thepropulsion unit 11B formed by the assistingwheel 23 is removed and replaced by apropulsion unit 11B comprising a drivencaterpillar track 43 connected to thebase frame 6. The operations of the propulsion system (formed by thepropulsion units support actuators 32 are controlled by thecontrol system 45 provided on thebase frame 6. - It will be apparent to those skilled in the art that various modifications can be made to the device and method without departing from the scope as defined in the claims.
Claims (21)
1.-66. (canceled)
67. A trenching device for forming a trench in a seabed to receive an elongate object, such as a pipeline, said trenching device comprising:
a base frame; and
a trenching wheel which is connected to the base frame and rotatable about a trenching wheel axis to form the trench, wherein the trenching device is configured to push the trenching wheel into the seabed when the trenching wheel is positioned on the seabed.
68. The trenching device according to claim 67 , wherein the trenching device comprises a ballast to push the trenching wheel into the seabed when the trenching wheel is positioned on the seabed.
69. The trenching device according to claim 67 , wherein the ballast is formed, or partly formed, by a ballast system.
70. The trenching device according to claim 69 , wherein the ballast system is configured to adjust the magnitude of the force working on the base frame.
71. The trenching device according to claim 69 , wherein the ballast system is configured to adjust the position of the force working on the base frame.
72. The trenching device according to claim 69 , wherein the ballast system comprises a ballast tank configured to hold a fluid, a pump system to pump water in the ballast tank, and the pump system is configured to pump gas in the ballast tank.
73. The trenching device according to claim 72 , wherein the ballast tank comprises multiple ballast compartments, the pump system is configured to pump water in multiple ballast compartments independently from each other, and the pump system is configured to pump gas in multiple ballast compartments independently from each other.
74. The trenching device according to claim 68 , wherein the trenching device comprises a front side and a rear side, the trenching device is configured to be moved in the direction from the rear side to the front side, the resultant force of the ballast acting on the base frame is located at a distance e beyond the trenching wheel axis when seen in the direction from the rear side to the front side.
75. The trenching device according to claim 67 , wherein the trenching device comprises a propulsion system formed by at least one propulsion unit which is connected to the base frame to move the trenching device along the seabed, and the base frame comprises a first frame part and a second frame part which are connected to each other via a pivot connection, the trenching wheel is connected to the first frame part, and at least one propulsion unit is connected to the second frame part.
76. The trenching device according to claim 75 , wherein at least one propulsion unit comprises an assisting wheel connected to the base frame and rotatable about an assisting wheel axis, and a further wheel drive to rotate the assisting wheel around the assisting wheel axis in order to move the trenching device along the seabed.
77. The trenching device according to claim 76 , wherein the assisting wheel in the direction of the assisting wheel axis comprises a thickness t3 and the thickness t3 remains constant in the direction from the assisting wheel axis to the outer circumference of the assisting wheel, and the thickness t3 is larger than t2 and smaller than t1 or the thickness t3 is larger than t2 and smaller than t2+0.5(t1−t2).
78. The trenching device according to claim 75 , wherein the second frame part is pivotable about a frame pivot axis relative to the first frame part, and the frame pivot axis extends perpendicular, or substantially perpendicular, to the trenching wheel axis.
79. The trenching device according to claim 75 , wherein the trenching device comprises a steering system configured to pivot the second frame part relative to the first frame part.
80. A method of forming a trench in a seabed to receive an elongate object, such as a pipeline, with a trenching device comprising a base frame, a trenching wheel which is connected to the base frame and rotatable about a trenching wheel axis to form the trench, wherein the trenching device is configured to push the trenching wheel into the seabed when the trenching wheel is positioned on the seabed, and said method comprises:
positioning the trenching wheel on the seabed;
pushing the trenching wheel into the seabed; and
moving the trenching device along the seabed to form the trench.
81. The method according to claim 80 , wherein the trenching device comprises a ballast, and the method comprises pushing the trenching wheel into the seabed by the weight of the ballast.
82. The method according to claim 80 , wherein the ballast is formed, or partly formed, by a ballast system configured to adjust the magnitude of the force of the ballast working on the base frame, and the method comprises adjusting the magnitude of the force of the ballast working on the base frame to push the trenching wheel into the seabed.
83. The method according to claim 82 , wherein the ballast system is configured to adjust the position of the force of the ballast working on the base frame, and the method comprises adjusting the position of the force of the ballast working on the base frame to push to trenching wheel into the seabed.
84. The method according to claim 82 , wherein the ballast system comprises a ballast tank configured to hold a fluid, and the method comprises filling the ballast tank with water to increase the magnitude of the force of the ballast working on the base frame, and the method comprises filling the ballast tank with air to decrease the magnitude of the force of the ballast working on the base frame and/or to create buoyancy such that the trenching device is neutrally buoyant or floats up in the water.
85. The method according to claim 80 , wherein the trenching device comprises a propulsion system formed by at least one propulsion unit connected to the base frame, and the method comprises moving the trenching device along the seabed with the propulsion system.
86. The method according to claim 85 , wherein the base frame comprises a first frame part and a second frame part which are connected to each other via a pivot connection, the trenching wheel is connected to the first frame part, at least one propulsion unit is connected to the second frame part, the trenching device comprises a steering system configured to pivot the second frame part relative to the first frame part, and the method comprises pivoting the second frame part relative to the first frame part to adjust the direction in which the trenching device is moved along the seabed.
Priority Applications (1)
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US14/420,596 US20150233088A1 (en) | 2012-08-10 | 2013-08-12 | Trenching device |
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US201261681915P | 2012-08-10 | 2012-08-10 | |
NL2009318A NL2009318C2 (en) | 2012-08-13 | 2012-08-13 | Trenching device. |
NL2009318 | 2012-08-13 | ||
PCT/NL2013/050594 WO2014025262A1 (en) | 2012-08-10 | 2013-08-12 | Trenching device |
US14/420,596 US20150233088A1 (en) | 2012-08-10 | 2013-08-12 | Trenching device |
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CA (1) | CA2880918A1 (en) |
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CN108999233B (en) * | 2018-07-31 | 2021-03-12 | 华北水利水电大学 | Hydraulic engineering desilting device |
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US7219452B1 (en) * | 2002-06-11 | 2007-05-22 | Raguse Steven F | Trench wheel apparatus and method of use |
GB2428437B (en) * | 2005-07-16 | 2007-08-08 | Dawn Violet Smith | Trench forming apparatus |
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2012
- 2012-08-13 NL NL2009318A patent/NL2009318C2/en not_active IP Right Cessation
-
2013
- 2013-08-12 WO PCT/NL2013/050594 patent/WO2014025262A1/en active Application Filing
- 2013-08-12 US US14/420,596 patent/US20150233088A1/en not_active Abandoned
- 2013-08-12 CA CA2880918A patent/CA2880918A1/en not_active Abandoned
- 2013-08-12 RU RU2015107985A patent/RU2015107985A/en not_active Application Discontinuation
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US3952532A (en) * | 1975-04-23 | 1976-04-27 | Spearman Robert R | Underwater trenching and cable laying apparatus |
US4116014A (en) * | 1976-05-06 | 1978-09-26 | Unit Rig And Equipment Co. | Excavating and pipeline installation system |
US4214387A (en) * | 1978-06-01 | 1980-07-29 | Brown & Root, Inc. | Trenching apparatus and method |
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RU2015107985A (en) | 2016-09-27 |
WO2014025262A1 (en) | 2014-02-13 |
NL2009318C2 (en) | 2014-02-18 |
CA2880918A1 (en) | 2014-02-13 |
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