Trenching assembly for laying in a trench a continuous pipeline and trenching method

Patent metadata

Field	Value
Publication number	US-10435865-B2
Application number	US-201615748114-A
Country	US
Kind code	B2
Filing date	Jul 26, 2016
Priority date	Jul 28, 2015
Publication date	Oct 8, 2019
Grant date	Oct 8, 2019

Abstract

A trenching assembly lays a continuous pipeline in a trench dug in a bed with uneven bathymetry, the trenching assembly including a trench digging device having a main body; at least four ground contact units, each unit having a height adjustment device, to position each ground contact unit with respect to the main body independently. A trench cutting tool digs in the bed includes a cutting depth adjustment device, for positioning the cutting tool with respect to the main body. A detection device detects bed bathymetry. A control device simultaneously allows cooperation between the detection device, the height adjustment device of each ground contact unit, and the cutting depth adjustment device. A command device cooperates with the control device to adjustment each ground contact unit and the cutting depth adjustment device, to obtain a trench having a height difference lower than a predefined tolerance and a predetermined burial depth.

First claim

The invention claimed is:

1. An underwater trenching assembly for laying a continuous pipeline in a trench dug in a bed, said continuous pipeline being buried in said trench, said trench extending predominantly along a longitudinal direction; said trenching assembly comprising:
a trench digging device, comprising:
a main body;
at least four ground contact units, wherein each ground contact unit comprises at least one height adjustment device for adjusting at least a position of each ground contact unit with respect to said main body independently from the other ground contact units;
at least one trench cutting tool, for digging in said bed to obtain said trench, wherein said trench cutting tool comprises a cutting depth adjustment device for adjusting the position of said cutting tool with respect to said main body;
at least one detection device, for detecting bathymetry of the bed during the excavation;
at least one control device, for simultaneously allowing cooperation between at least:
said detection device, and
said height adjustment device of each of said ground contact units, and
said cutting depth adjustment device;

at least one command device, said at least one command device cooperating with said at least one control device for adjusting said height adjustment device of each of said ground contact units and said cutting depth adjustment device, to obtain said trench having a height difference along the longitudinal direction lower than a predefined tolerance and having a predetermined burial depth;
wherein said control device compares at least information on the bathymetry with said predefined tolerance and with said predefined burial depth, to generate an expected digging profile;
wherein said control device cooperates with said command device to adjust at least said cutting depth adjustment device to make a trench having a trench bottom substantially corresponding to said expected digging profile; and
wherein said control device comprises at least one first data processing unit, for processing information at least on the bathymetry of the bed and at least one second data processing unit, for automatically actuating said command device to adjust said height adjustment device and said cutting depth adjustment device.

2. The underwater trenching assembly according to claim 1 , wherein said control device comprises at least one first data processing unit, for processing information at least on the bathymetry of the bed and a control room, for reporting information on the bathymetry of the bed to an operator, and wherein said operator actuates said command device to adjust said height adjustment device and said cutting depth adjustment device.

3. The underwater trenching assembly according to claim 1 , wherein said detection device detects, during excavation, a position of at least one portion of said continuous pipeline, and/or wherein said detection device is suitable for detecting during the excavation position of said pipeline portion to be buried; and/or wherein said detection device detects, during the excavation, position of said at least one suspended pipeline portion; and/or wherein said first data processing unit separates information on the bathymetry of the bed from information on positioning of a pipeline portion to be laid.

4. The underwater trenching assembly according to a claim 1 , comprising at least one from among:
a support vehicle, adapted to supply said trench digging device;
a detection device, for being connected at least to said trench digging device;
a mechanical arm, for being connected at least mechanically to said main body; and
wherein at least one from among said support vehicle, said detection device and said mechanical arm comprises said detection device.

5. The underwater trenching assembly according to claim 4 , wherein said detection device is a remotely operated submarine or ROV.

6. The underwater trenching assembly according to claim 1 , wherein each of said at least four ground contact units is connected to said main body by at least one leg, for driving relative movement between said ground contact unit and said main body; and/or
wherein each of said at least one leg is connected to a respective ground contact unit by a first mechanical joint, for allowing free rotation between said leg and said respective ground contact unit in a movement plane; and/or
wherein said first mechanical joint, for allowing the free rotation between said leg and said respective ground contact unit in said movement plane, allows relative movements about an axis orthogonal to said movement plane, or pitch axis, between said leg and said respective ground contact unit; and/or
wherein said height adjustment device simultaneously and selectively adjusts the position of said ground contact unit with respect to said main body, and the movement about the pitch axis of said ground contact unit independently from the other ground contact units.

7. The underwater trenching assembly according to claim 1 , wherein said control device actuates a feedback control on inclination of said main body to actuate said control device to adjust at least said height adjustment device of at least one of said ground contact units, to maintain constant balance conditions, or gradually variable balance conditions, of said trench digging device; and/or
wherein to maintain the constant balance conditions, or gradually variable balance conditions, a range of variation of the inclination angle of the main body is between 0° and 5° every 10 meters of movement of the trench digging device on the bed; and/or
wherein said control device performs a feedback loop control on a position of said cutting tool to actuate said command device to adjust said height adjustment device of at least one of said ground contact units and/or said cutting depth adjustment device, to maintain the constant balance conditions, or gradually variable balance conditions of said trench digging device; and/or
wherein to maintain the constant balance conditions, or gradually variable balance conditions, the range of variation of the inclination angle of the main body is between 0° and 5° every 10 meters of movement of the trench digging device on the bed.

8. The underwater trenching assembly according to claim 1 ; wherein said trench digging device comprises said detection device, said control device and said command device to arrange on a single trench digging device the components for automatically controlling and carrying out the digging of a trench having said predetermined burial depth and a height difference along the longitudinal direction less than said predefined tolerance.

9. The underwater trenching device according to claim 1 , comprising at least one mechanical arm for connecting at least mechanically to said main body of said trench digging device, wherein said mechanical arm comprises said detection device and is primarily for detecting the bathymetry of bed portions arranged in an advancing direction of the trench digging device.

10. The underwater trenching assembly according to claim 1 , wherein said main body of said trench digging device comprises said control device; and/or wherein said main body of said trench digging device comprises said command device.

11. The underwater trenching device according to claim 1 , wherein said detection device comprises an acoustic localization device or said detection device comprises a laser.

12. Method for laying a continuous pipeline in an underwater trench dug in a bed, comprising the steps of:
providing a trenching assembly according to claim 1 ;
detecting bathymetry of the bed;
using bathymetry information to independently adjust t

Assignees

• Saipem Spa

Inventors

• Bonel Paolo
• Lazzarin Diego
• Serena Alberto

Classifications

• E02F5/109

  using rotating digging elements (rotating digging elements per se E02F3/18) · CPC title

• E02F5/106

  using ploughs, coulters, rippers · CPC title

• E02F5/107

  using blowing-effect devices, e.g. jets (digging devices using a blowing effect per se E02F3/9206) · CPC title

• F16L1/16

  on the bottom · CPC title

• E02F5/105 Primary

  self-propulsed units moving on the underwater bottom · CPC title