WO2017078528A1

WO2017078528A1 - Welding system and method for filling a welding groove of a branch connection between a first pipe section and a second pipe section

Info

Publication number: WO2017078528A1
Application number: PCT/NL2016/050769
Authority: WO
Inventors: Jojakim Adriaan Martien HERREBOUT; Cornelis Arie SPAANS
Original assignee: Heerema Fabrication Group Se
Priority date: 2015-11-05
Filing date: 2016-11-04
Publication date: 2017-05-11
Also published as: NL2015726B1

Abstract

A welding system for filling a welding groove of a branch connection between a first pipe section and a second pipe section, said system comprising a support device configured to support the first pipe section and the second pipe section in a horizontal manner, a first robot arm, a second robot arm, a scanner, and a control unit.

Description

WELDING SYSTEM AND METHOD FOR FILLING A WELDING GROOVE OF A BRANCH

CONNECTION BETWEEN A FIRST PIPE SECTION AND A SECOND PIPE SECTION FIELD OF THE INVENTION

The invention relates to a welding system for filling a welding groove of a branch connection between a first pipe section and a second pipe section. The first pipe section comprises a first wall surrounding a first longitudinal axis. The second pipe section comprises a second wall surrounding a second longitudinal axis and a pipe end having an end rim. A first rim part of the end rim is connected to the first wall and a second rim part of the end rim is located at a distance from the first wall to form the welding groove.

In practise this is often referred to that the second pipe section is "fitted" to the first pipe section. This means that the first rim part of the end rim of the second pipe section is welded in such a manner that the connection is only sufficient strong to keep the two pipe sections together without additional support. The fitting can for example be formed by spot welding or it can contain the root pass. The welding groove will subsequently be filled in order to form a strong connection between the two pipe sections. BACKGROUND OF THE INVENTION

These branch connections are in practise used to form large and heavy structures, such as jackets (the support legs) of oil platforms at sea. Due to fact that very large pipe sections are used for the construction of the jackets, the welding groove is also very large. The invention is based on the insight that there is a need to fill the welding groove in an efficient manner.

SUMMARY OF THE INVENTION

The invention has the objective to provide an improved, or at least alternative welding, system for filling a welding groove of a branch connection between a first pipe section and a second pipe section.

The welding system is suitable for filling a welding groove of a branch connection between a first pipe section and a second pipe section, wherein the first pipe section comprises a first wall surrounding a first longitudinal axis, the second pipe section comprises a second wall surrounding a second longitudinal axis and a pipe end having an end rim, and a first rim part of the end rim is connected to the first wall and a second rim part of the end rim is located at a distance from the first wall to form the welding groove, said system comprising;

- a support device configured to support the first pipe section and the second pipe section with the first longitudinal axis and the second longitudinal axis extending substantially horizontally,

- a first robot arm being connected to a first support frame at a first mounting base, which first mounting base is located above a horizontal plane extending through the first longitudinal axis of the first pipe section, wherein the first robot arm is provided with a first welding head and constructed to move the first welding head along a first part of the welding groove located above the horizontal plane,

- a second robot arm being connected to a second support frame at a second mounting base, which second mounting base is located below the horizontal plane extending through the first longitudinal axis of the first pipe section, wherein the second robot arm is provided with a second welding head and constructed to move the second welding head along a second part of the welding groove located below the horizontal plane,

- a scanner configured to scan the complete welding groove in order to provide data about the welding groove,

- a control unit which is in communication connection with the first and second robot arm and the scanner and configured to, on basis of the data provided by the scanner, determine a first welding trajectory for the first welding head to provide a first weld in the welding groove and a second welding trajectory for the second welding head to provide a second weld in the welding groove, wherein the first welding trajectory extends above the horizontal plane, the second welding trajectory extends below the horizontal plane and the first and second weld together form a weld layer which completely surrounds the second longitudinal axis, and wherein the control unit is further configured to repeat said scanning of the welding groove with the scanner and subsequently said welding with the first and second welding head until the welding groove is filled with weld layers

Due to the fact that the two interconnected pipe sections are placed with their longitudinal axis extending horizontally and the welding is performed with two welding heads moving along the defined welding trajectories, it is possible that the welding system performs the welding automatically with the two robots arms being connected to their defined mounting base.

The data provided by the scanner relates to the form and location of the welding groove.

In an embodiment of the welding system according to the invention, the first and second robot arm and free from any supporting connection with the first and second pipe section. In an embodiment of the welding system according to the invention, the welding system comprises a first driver to move the first mounting base of the first robot arm along a first straight horizontal trajectory and a second driver to move the second mounting base of the second robot arm along a second straight horizontal trajectory. This facilitates the welding of along the defined welding trajectories.

In an embodiment of the welding system according to the invention, the second longitudinal axis of the second pipe section extends under an angle of between 30 and 150 degrees to the first longitudinal axis of the first pipe section when seen in a plane extending through the first and second longitudinal axis.

In an embodiment of the welding system according to the invention, the first and second straight horizontal trajectory extend substantially parallel to each other. In an embodiment of the welding system according to the invention, the support device is configured to support the first and second pipe section with the first longitudinal axis extending substantially parallel to the first straight horizontal trajectory.

In an embodiment of the welding system according to the invention, the support device is configured to support the first and second pipe section with the first longitudinal axis extending substantially parallel to the second straight horizontal trajectory.

In an embodiment of the welding system according to the invention, the first welding trajectory extends over more than 50 % of the welding groove and the second welding trajectory extends over less than 50 % of the welding groove.

In an embodiment of the welding system according to the invention, the first welding trajectory extends between 55-75 % of the welding groove and the second welding trajectory extends over 25-45 % of the welding groove.

In an embodiment of the welding system according to the invention, the first welding trajectory extends over around 60 % of the welding groove and the second welding trajectory extends around over 40 % of the welding groove. In an embodiment of the welding system according to the invention, the first welding trajectory also extends along part of the welding groove located below the horizontal plane and the second welding trajectory only extends along part of the welding groove located below the horizontal plane.

In an embodiment of the welding system according to the invention, the first welding trajectory extends from a left intermediate weld location along a top weld location until a right intermediate weld location, the first welding head is during welding moved from the left intermediate weld location to the top weld location and subsequently from the right intermediate weld location to the top weld location, the second welding trajectory extends from the left intermediate weld location along a bottom weld location until the right intermediate weld location, and the second welding head is during welding moved from the bottom weld location to the right intermediate weld location and subsequently from the bottom weld location to the left intermediate weld location.

The first and second welding head may be moved one or multiple times along the first and second trajectory to provide one or multiple first and second welds in order to form the weld layer in the welding groove.

In an alternative embodiment of the welding system according to the invention, the first welding trajectory extends from a left intermediate weld location along a top weld location until a right intermediate weld location, the first welding head is during welding moved from the right intermediate weld location to the top weld location and subsequently from the left intermediate weld location to the top weld location, the second welding trajectory extends from the left intermediate weld location along a bottom weld location until the right intermediate weld location, and the second welding head is during welding moved from the bottom weld location to the left intermediate weld location and subsequently from the bottom weld location to the right intermediate weld location.

In an embodiment of the welding system according to the invention, the left intermediate weld location and the right intermediate weld location are located in the horizontal plane extending through the first longitudinal axis of the first pipe section, and the top weld location is located above and the bottom weld location is located below said horizontal plane.

In an embodiment of the welding system according to the invention, the left intermediate weld location and the right intermediate weld location are located below the horizontal plane extending through the first longitudinal axis of the first pipe section. This can be

advantageous because, because due the location of the (upper) first welding trajectory, the welding with the first welding head may go faster than the second welding head. In an embodiment of the welding system according to the invention;

- the first welding head is operatively coupled to the first robot arm in a releasable manner and the second welding head is operatively coupled to the second robot arm in a releasable manner,

- the scanner comprises a first scan head and a second scan head,

- the first robot arm is configured to be operatively coupled to the first scan head and the second robot arm is configured to be operatively coupled to the second scan head,

- the control unit is configured to move the first scan head with the first robot arm along a first scan trajectory extending along the welding groove and above the horizontal plane and configured to move the second scan head with the second robot arm along a second scan trajectory extending along the welding groove and below the horizontal plane in order to scan the welding groove, wherein the first and second scan trajectory together completely surround the second longitudinal axis. In an embodiment of the welding system according to the invention, the first scan head and the second scan head comprise a first temperature sensor and a second temperature sensor, respectively, to measure the temperature in the welding groove.

In an embodiment of the welding system according to the invention, the first scan trajectory extends from a left intermediate scan location along a top scan location until a right intermediate scan location, the first scan head is during scanning moved from the left intermediate scan location to the top scan location and subsequently from the right intermediate scan location to the top scan location, the second scan trajectory extends from the left intermediate scan location along a bottom scan location until the right intermediate scan location, the second scan head is during scanning moved from the bottom scan location to the right intermediate scan location and subsequently from the bottom scan location to the left intermediate scan location, the left intermediate scan location and the right intermediate scan location are located in the horizontal plane extending through the first longitudinal axis of the first pipe section, and the top scan location is located above and the bottom scan location is located below said horizontal plane.

The first and second scan head may be moved one or multiple times along the first and second trajectory to scan the welding groove. In an embodiment of the welding system according to the invention, the first scan trajectory extends from a left intermediate scan location along a top scan location until a right intermediate scan location, the first scan head is during scanning moved from the right intermediate scan location to the top scan location and subsequently from the left intermediate scan location to the top scan location, the second scan trajectory extends from the left intermediate scan location along a bottom scan location until the right intermediate scan location, the second scan head is during scanning moved from the bottom scan location to the left intermediate scan location and subsequently from the bottom scan location to the right intermediate scan location, the left intermediate scan location and the right intermediate scan location are located in the horizontal plane extending through the first longitudinal axis of the first pipe section, and the top scan location is located above and the bottom scan location is located below said horizontal plane.

In an embodiment of the welding system according to the invention, the welding system comprises an input device to provide information to the control unit about the first and second scan trajectories along which the first and second scan head are moved to obtain data for the first weld layer which will be provided in the welding groove by the first and second welding head.

In an embodiment of the welding system according to the invention, the first welding trajectory differs from the first scan trajectory and the second welding trajectory differs from the second scan trajectory.

In an embodiment of the welding system according to the invention, the control unit is configured to optimise the first welding trajectory on basis of welding characteristics of the first welding head and the second welding trajectory on basis of welding characteristics of the second welding head.

In an embodiment of the welding system according to the invention, the welding system comprises an input device to provide information for the operation of the first and second welding head to the control unit. In an embodiment of the welding system according to the invention, the control unit is configured to optimise the first scan trajectory on basis of scanning characteristics of the first scan head and the second scan trajectory on basis of scan characteristics of the second scan head. In an embodiment of the welding system according to the invention, the welding system comprises an input device to provide information for the operation of the first and second scan head to the control unit. In an embodiment of the welding system according to the invention;

- the system comprises a first slag head and a second slag head, which are both configured to remove slag from the weld layer,

- the first robot arm is configured to be operatively coupled to the first slag head and the first robot arm is configured to be operatively coupled to the first slag head,

- the control unit is configured to, on the basis of the data of the scanner, determine a first slag trajectory for the first slag head to remove slag from the weld layer and a second slag trajectory for the second slag head to remove slag from the weld layer, wherein the first slag trajectory extends above the horizontal plane, the second slag trajectory extends below the horizontal plane and the first and second slag trajectory together completely surround the second longitudinal axis.

In an embodiment of the welding system according to the invention, the control unit is configured to after the weld layer is provided in the welding groove by the first and second welding head, remove slag from said weld layer with the first and second slag head.

In an embodiment of the welding system according to the invention, the first welding trajectory is equal to the first slag trajectory and the second welding trajectory is equal to the second slag trajectory.

In an embodiment of the welding system according to the invention, the first welding trajectory differs from the first slag trajectory and the second welding trajectory differs from the second slag trajectory. In an embodiment of the welding system according to the invention, the control unit is configured to optimise the first slag trajectory on basis of the slag removal characteristics of the first scan head and the second slag trajectory on basis of slag removal characteristics of the second scan head. In an embodiment of the welding system according to the invention, the welding system comprises an input device to provide information for the operation of the first and second slag head to the control unit.

In an embodiment of the welding system according to the invention, the first slag trajectory extends from a left intermediate slag location along a top slag location until a right intermediate slag location, the first slag head is during removal of slag moved from the top slag location to the left intermediate slag location and subsequently from the top slag location to the right intermediate slag location, the second slag trajectory extends from the left slag weld location along a bottom slag location until the right intermediate slag location, and the second slag head is during removal of slag moved from the right intermediate slag location to the bottom slag location and subsequently from the left intermediate slag location to the bottom slag location.

The first and second slag head may be moved one or multiple times along the first and second trajectory to remove slag from the weld layer in the welding groove. In an alternative embodiment of the welding system according to the invention, the first slag trajectory extends from a left intermediate slag location along a top slag location until a right intermediate slag location, the first slag head is during removal of slag moved from the top slag location to the right intermediate slag location and subsequently from the top slag location to the left intermediate slag location, the second slag trajectory extends from the left slag weld location along a bottom slag location until the right intermediate slag location, the second slag head is during removal of slag moved from the left intermediate slag location to the bottom slag location and subsequently from the right intermediate slag location to the bottom slag location. In an embodiment of the welding system according to the invention, the left intermediate slag location and the right intermediate slag location are located in the horizontal plane extending through the first longitudinal axis of the first pipe section, and top slag location is located above and the bottom slag location is located below said horizontal plane. In an embodiment of the welding system according to the invention, the first and second robot arm are each configured to move the first and second welding head, respectively, with at least 6 degrees of freedom.

In an embodiment of the welding system according to the invention, the control unit is configured to control the system in order to;

- scan the welding groove by operatively coupling the first scan head to the first robot arm and operatively coupling the second scan head to the second robot arm, subsequently scanning the complete welding groove with the first scan head and the second scan head, and subsequently decoupling the first scan head from the first robot arm and decoupling the second scan head from the second robot arm, and

- provide the weld layer by operatively coupling the first welding head to the first robot arm and operatively coupling the second welding head to the second robot arm, subsequently providing the first weld with the first welding head and providing the second weld with the second welding head, and subsequently decoupling the first welding head from the first robot arm and decoupling the second welding head from the second robot arm. In an embodiment of the welding system according to the invention, the control unit is configured to control the system in order to, after decoupling the first welding head from the first robot arm and decoupling the second welding head from the second robot arm, operatively coupling the first slag head to the first robot arm and operatively coupling the second slag head to the second robot arm, subsequently removing slag from the complete weld layer with the first slag head and the second slag head, and subsequently decoupling the first slag head from the first robot arm decoupling the second slag head from the second robot arm.

In an embodiment of the welding system according to the invention, the first support frame and the second support frame are formed by a single support frame.

Method of filling a welding groove of a branch connection between a first pipe section and a second pipe section, wherein the first pipe section comprises a first wall surrounding a first longitudinal axis, the second pipe section comprises a second wall surrounding a second longitudinal axis and a pipe end having an end rim, and a first rim part of the end rim is connected to the first wall and a second rim part of the end rim is located at a distance from the first wall to form the welding groove, said method comprising the steps of;

- supporting the first and second pipe section with a support device of a welding system according to any of the preceding claims, such that the first pipe section is positioned with the first longitudinal axis extending substantially horizontally and the second pipe section is positioned with the second longitudinal axis extending substantially horizontally,

- scanning the complete welding groove with the scanner to provide data about the welding groove,

- on basis of said data, providing the first weld in the welding groove with the first welding head moving along the first welding trajectory and providing the second weld in the welding groove with the second welding head moving along the second welding trajectory to form the weld layer which completely surrounds the second longitudinal axis of the second pipe section, and

- repeating said scanning of the welding groove with the scanner and subsequently welding of with the first and second welding head until the welding groove is filled with weld layers.

In an embodiment of the method according to the invention, the method comprises; - the scanning of the welding groove comprises operatively coupling the first scan head to the first robot arm and operatively coupling the second scan head to the second robot arm, subsequently moving the first scan head along the first scan trajectory and moving the second scan head along the second scan trajectory in order to scan the complete welding groove, and subsequently decoupling the first scan head from the first robot arm and decoupling the second scan head from the second robot arm, and

- the providing of the weld layer comprises operatively coupling the first welding head to the first robot arm and operatively coupling the second welding head to the second robot arm, subsequently providing the first weld with the first welding head and providing the second weld with the second welding head, and subsequently decoupling the first welding head from the first robot arm and decoupling the second welding head from the second robot arm.

In an embodiment of the method according to the invention, the providing of the weld layer comprises, after decoupling the first welding head from the first robot arm and decoupling the second welding head from the second robot arm, performing the steps of operatively coupling the first slag head to the first robot arm and operatively coupling the second slag head to the second robot arm, subsequently moving the first slag head along the first slag trajectory and moving the second slag head along the second slag trajectory in order to remove slag from the complete weld layer, and subsequently decoupling the first slag head from the first robot arm decoupling the second slag head from the second robot arm.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the welding system and 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;

Figure 1 schematically show a view in perspective of an embodiment of the welding system according to the invention,

Figure 2 schematically show a side view of the welding system of figure 1 ,

Figure 3 schematically show a top view of the welding system of figure 1 ,

Figure 4 schematically show a side view of the welding system of figure 1 ,

the Figures 5 and 6 schematically show a side view of the interconnected first and second pipe section,

Figure 7 schematically shows a view in cross section along the second longitudinal axis of the interconnected first and second pipe section of figure 5,

Figure 8 schematically shows a view in perspective of the welding system of figure 1 with the interconnected first and second pipe section of figure 5, Figure 9 schematically show a side view of the welding system of figure 1 with the interconnected first and second pipe section of figure 5,

Figure 10 schematically shows a top view of the welding system of figure 1 with the interconnected first and second pipe section of figure 5,

the Figures 1 1-18 schematically show the scanning of the welding groove with the welding system of figure 1 on the interconnected first and second pipe section of figure 5, the Figures 19-27 schematically show the welding of the welding groove with the welding system of figure 1 on the interconnected first and second pipe section of figure 5, the Figures 28-35 schematically show the removal of slag from the welding groove with the welding system of figure 1 on the interconnected first and second pipe section of figure 5, the Figures 36 and 37 schematically show a view in perspective and a side view of the welded first and second pipe section, and

Figure 38 schematically shows a view in cross section along the second longitudinal axis of the welded first and second pipe section of figure 36.

DETAILED DESCRIPTION OF THE DRAWINGS

The figures 1-4 show a view in perspective of an embodiment of the welding system 1 according to the invention. The welding system 1 is configured to fill a welding groove 2 of a branch connection between a first pipe section 4 and a second pipe section 5.

The branch connection and the welding groove 2 are shown more in detail in the figures 5-7. The first pipe section 4 comprises a first wall 6 surrounding a first longitudinal axis 7. The second pipe section 5 comprises a second wall 8 surrounding a second longitudinal axis 9 and a pipe end 10 having an end rim 1 1. A first rim part 12 of the end rim 1 1 is connected to the first wall 6 and a second rim part 13 of the end rim 1 1 is located at a distance from the first wall 6 to form the welding groove 2. A welded root pass 58 ensures that the second pipe section 5 is fitted to the first pipe section 4. The welding system 1 comprises a support device 14 configured to support the first pipe section 4 and the second pipe section 5 with the first longitudinal axis 7 and the second longitudinal axis 9 extending substantially horizontally.

In the figures 8-9, the interconnected first and second pipe section 5 are supported on the support device 14 of the welding system 1 of figure 1. A first robot arm 15 is connected to a first support frame 16 at a first mounting base 17. The first mounting base 17 is located above a horizontal plane extending through the first longitudinal axis 7 of the first pipe section 4. The first robot arm 15 is provided with a first welding head 19 and constructed to move the first welding head 19 along a first part 20 of the welding groove 2 located above the horizontal plane.

A second robot arm 21 is connected to a second support frame 22 at a second mounting base 23. The second mounting base 23 is located below the horizontal plane extending through the first longitudinal axis 7 of the first pipe section 4. The second robot arm 21 is provided with a second welding head 24 and constructed to move the second welding head 24 along a second part 25 of the welding groove 2 located below the horizontal plane.

The welding system 1 further comprises a scanner 41 , 42 configured to scan the complete welding groove 2 in order to provide data about the welding groove 2.

A control unit 27 is in communication connection with the first and second robot arm 15, 21 and the scanner 41 , 42 and configured to, on basis of the data provided by the scanner 41 , 42, determine a first welding trajectory 28 for the first welding head 19 to provide a first weld 31 in the welding groove 2 and a second welding trajectory 32 for the second welding head 24 to provide a first weld 35 in the welding groove 2. The first welding trajectory 28 extends above the horizontal plane. The second welding trajectory 32 extends below the horizontal plane. The first and second weld 31 , 35 together form a weld layer 36 which completely surrounds the second longitudinal axis 9. The control unit 27 is further configured to repeat said scanning of the welding groove 2 with the scanner 41 , 42 and subsequently said welding with the first and second welding head 19, 24 until the welding groove 2 is filled with weld layers 36.

The first and second robot arm 15, 21 are free from any supporting connection with the first and second pipe section 4, 5. The first support frame 16 and the second support frame 22 are formed by a single support frame 57.

The welding system 1 comprises a first driver 37 to move the first mounting base 17 of the first robot arm 15 along a first straight horizontal trajectory 38 and a second driver 39 to move the second mounting base 23 of the second robot arm 21 along a second straight horizontal trajectory 40. The first and second straight horizontal trajectory 38, 40 extend substantially parallel to each other.

The support device 14 is configured to support the first and second pipe section 4, 5 with the first longitudinal axis 7 extending substantially parallel to the first and second straight horizontal trajectory 38, 40.

The first welding head 19 is operatively coupled to the first robot arm 15 in a releasable manner and the second welding head 24 is operatively coupled to the second robot arm 21 in a releasable manner. The scanner 41 , 42 comprises a first scan head 41 and a second scan head 42. The first robot arm 15 is configured to be operatively coupled to the first scan head 41 and the second robot arm 21 is configured to be operatively coupled to the second scan head 42. The control unit 27 is configured to move the first scan head 41 with the first robot arm 15 along a first scan trajectory 43 extending along the welding groove 2 and above the horizontal plane and configured to move the second scan head 42 with the second robot arm 21 along a second scan trajectory 46 extending along the welding groove 2 and below the horizontal plane in order to scan the welding groove 2. The first and second scan trajectory together completely surround the second longitudinal axis 9. The welding system 1 comprises an input device 61 to provide information to the control unit 27. The input device 61 is configured to provide information about the first and second scan trajectory along which the first and second scan head are moved to obtain data for the first weld layer 36 which will be provided in the welding groove by the first and second welding head.

The first scan head 41 and the second scan head 42 comprise a first temperature sensor and a second temperature sensor, respectively, to measure the temperature in the welding groove 2. The control unit 27 is configured to optimise the first welding trajectory 28 on basis of welding characteristics of the first welding head 19 and the second welding trajectory 32 on basis of welding characteristics of the second welding head 24.

The input device 61 is configured to provide information for the operation of the first and second welding head to the control unit 27. The control unit 27 is configured to optimise the first scan trajectory 43 on basis of scanning characteristics of the first scan head 41 and the second scan trajectory 46 on basis of scan characteristics of the second scan head 42. The input device 61 is configured to provide information for the operation of the first and second scan head 42 to the control unit 27.

The system comprises a first slag head 49 and a second slag head 50, which are both configured to remove slag from the weld layer 36. The first robot arm 15 is configured to be operatively coupled to the first slag head 49 and the first robot arm 15 is configured to be operatively coupled to the first slag head 49. The control unit 27 is configured to, on the basis of the data of the scanner 41 , 42, determine a first slag trajectory 51 for the first slag head 49 to remove slag from the weld layer 36 and a second slag trajectory 54 for the second slag head 50 to remove slag from the weld layer 36. The first slag trajectory 51 extends above the horizontal plane, the second slag trajectory 54 extends below the horizontal plane and the first and second slag trajectory 54 together completely surround the second longitudinal axis 9.

The control unit 27 is configured to after the weld layer 36 is provided in the welding groove 2 by the first and second welding head, remove slag from said weld layer 36 with the first and second slag head. The first and second slag unit are configured to provide a vibrating force on the weld layer to remove slag.

The control unit 27 is configured to optimise the first slag trajectory 51 on basis of the slag removal characteristics of the first scan head 41 and the second slag trajectory 54 on basis of slag removal characteristics of the second scan head 42.

The first and second robot arm 15, 21 are each configured to move the first and second welding head, respectively, with at least 6 degrees of freedom.

The control unit 27 is configured to control the welding system 1 in order to;

- scan the welding groove 2 by operatively coupling the first scan head 41 to the first robot arm 15 and operatively coupling the second scan head 42 to the second robot arm 21 , subsequently scanning the complete welding groove 2 with the first scan head 41 and the second scan head 42, and subsequently decoupling the first scan head 41 from the first robot arm 15 and decoupling the second scan head 42 from the second robot arm 21 , and - provide the weld layer 36 by operatively coupling the first welding head 19 to the first robot arm 15 and operatively coupling the second welding head 24 to the second robot arm 21 , subsequently providing the first weld 31 with the first welding head 19 and providing the first weld 35 with the second welding head 24, and subsequently decoupling the first welding head 19 from the first robot arm 15 and decoupling the second welding head 24 from the second robot arm 21.

The control unit 27 is configured to control the system in order to, after decoupling the first welding head 19 from the first robot arm 15 and decoupling the second welding head 24 from the second robot arm 21 , operatively coupling the first slag head 49 to the first robot arm 15 and operatively coupling the second slag head 50 to the second robot arm 21 , subsequently removing slag from the complete weld layer 36 with the first slag head 49 and the second slag head 50, and subsequently decoupling the first slag head 49 from the first robot arm 15 decoupling the second slag head 50 from the second robot arm 21.

The procedure of filling the welding groove 2 will be further explained with reference to the figures 11-38.

Before the welding system 1 is activated (i.e., during the preparation phase), the first and second pipe section 4, 5 are fitted manually: the two pipe sections are brought into their correct relative position and this relative position is fixated by welding temporary metal parts between the two pipe sections, creating a single rigid construction (see figure 7).

The fitted pipe sections are then positioned on the support device 14 of the welding system 1 at a certain relative position and orientation (see figure 8). The outer diameter, wall thickness and length of all pipe sections and their relative joint angles are entered into the control unit 27 via the input device 61.

After that, the welding system 1 scans the complete welding groove 2 with the scanner 41 , 42 to provide data about the welding groove 2. The figures 1 1-18 schematically shows the scanning of the welding groove 2 with the welding system 1 of figure 1 on the interconnected first and second pipe section 4, 5 of figure 5.

In figure 1 1 are the first robot arm 15 and the second robot arm 21 moved to the stored first scan head 41 and second scan head 42, respectively, to operatively couple the scan heads to the robot arms. Figure 12 shows an enlarged view of part XII of figure 11 , which shows the first robot arm 15 in detail. A similar situation can be found at the second robot arm 21. In the figures 13 and 14 are the first and second scan head moved along the first and second scan trajectory 43, 46 by the first and second robot arm 15, 21. Figure 15 shows an enlarged view of part XV of figure 14, which shows the first robot arm 15 in detail. A similar situation can be found at the second robot arm 21.

The first and second scan trajectory 43, 46 are shown in figure 14, which shows a side view of the interconnected first and second pipe section 5 in the direction of the second longitudinal axis 9. The first scan trajectory 43 extends from a left intermediate scan location 47 along a top scan location 44 until a right intermediate scan location 48. The first scan head 41 is during scanning moved from the left intermediate scan location 47 to the top scan location 44 and subsequently from the right intermediate scan location 48 to the top scan location 44. The second scan trajectory 46 extends from the left intermediate scan location 47 along a bottom scan location 45 until the right intermediate scan location 48. The second scan head 42 is during scanning moved from the bottom scan location 45 to the right intermediate scan location 48 and subsequently from the bottom scan location 45 to the left intermediate scan location 47. The left intermediate scan location 47 and the right intermediate scan location 48 are located in the horizontal plane extending through the first longitudinal axis 7 of the first pipe section 4. The top scan location 44 is located above and the bottom scan location 45 is located below said horizontal plane. The first and second scan head 42 may be moved one or multiple times along the first and second trajectory to scan the welding groove 2. The first and second scan head also measure the temperature in the welding groove 2.

The first robot arm 15 and the second robot arm 21 place in figure 17 the first scan head 41 and the second scan head 42 back at their storage position to decouple the scan heads from the robot arms. Figure 18 shows an enlarged view of part XVIII of figure 17, which shows the first robot arm 15 in detail. A similar situation can be found at the second robot arm 21.

The first and second robot arm 15, 21 are now free to provide a weld layer 36 in the welding groove 2 on basis of the data from the scanner 41 , 42. This is shown in the figures 19-27.

In figure 19 are the first robot arm 15 and the second robot arm 21 moved to the stored first welding head 19 and second welding head 24, respectively, to operatively couple the welding heads to the robot arms. Figure 20 shows an enlarged view of part XX of figure 19, which shows the first robot arm 15 in detail. A similar situation can be found at the second robot arm 21. In the figures 21 and 22 are the first and second welding head moved along the first and second welding trajectory 29, 32 by the first and second robot arm 15, 21. Figure 23 shows an enlarged view of part XXIII of figure 22 which shows the first robot arm 15 in detail. A similar situation can be found at the second robot arm 21.

The first and second welding trajectory 29, 32 are shown in figure 24, which shows a side view of the interconnected first and second pipe section 4, 5 in the direction of the second longitudinal axis 9. The first welding trajectory 28 extends from a left intermediate weld location 33 along a top weld location 29 until a right intermediate weld location 34. The first welding head 19 is during welding moved from the left intermediate weld location 33 to the top weld location 29 and subsequently from the right intermediate weld location 34 to the top weld location 29. This way the first weld 31 is provided in the welding groove 2. The second welding trajectory 32 extends from the left intermediate weld location 33 along a bottom weld location 30 until the right intermediate weld location 34. The second welding head 24 is during welding moved from the bottom weld location 30 to the right intermediate weld location 34 and subsequently from the bottom weld location 30 to the left intermediate weld location 33. This way the first weld 35 is provided in the welding groove 2. The left intermediate weld location 33 and the right intermediate weld location 34 are located in the horizontal plane extending through the first longitudinal axis 7 of the first pipe section 4. The top weld location 29 is located above and the bottom weld location 30 is located below said horizontal plane. The first and second welding head 24 may be moved one or multiple times along the first and second trajectory to provide one or multiple first and second welds 31 , 35 in order to form the weld layer 36 in the welding groove 2. The first and second welding trajectory 28, 32 each extends in figure 24 over 50 % of the welding groove 2. An alternative embodiment is shown in figure 24, in which the first welding trajectory 28 extends over more than 50 % of the welding groove 2 and the second welding trajectory 32 extends over less than 50 % of the welding groove 2. The first welding trajectory 28 also extends along part of the welding groove 2 located below the horizontal plane and the second welding trajectory 32 only extends along part of the welding groove 2 located below the horizontal plane. The left intermediate weld location 33 and the right intermediate weld location 34 are located below the horizontal plane extending through the first longitudinal axis 7 of the first pipe section 4. This can be advantageous because, because due the location of the (upper) first welding trajectory 28, the welding with the first welding head may go faster than the second welding head. The first robot arm 15 and the second robot arm 21 place in figure 26 the first welding head 19 and the second welding head 24 back at their storage position to decouple the welding heads from the robot arms. Figure 27 shows an enlarged view of part XXVII of figure 26, which shows the first robot arm 15 in detail. A similar situation can be found at the second robot arm 21.

The first and second robot arm 15, 21 are now free to remove slag from the weld layer 36 in the welding groove 2 on basis of the data from the scanner 41 , 42. This is shown in the figures 28-35.

In figure 28 are the first robot arm 15 and the second robot arm 21 moved to the stored first slag head 49 and second slag head 50, respectively, to operatively couple the slag heads to the robot arms. Figure 29 shows an enlarged view of part XXIX of figure 28, which shows the first robot arm 15 in detail. A similar situation can be found at the second robot arm 21.

In the figures 30 and 31 are the first and second slag head moved along the first and second slag trajectory by the first and second robot arm 15, 21. Figure 32 shows an enlarged view of part XXXII of figure 31 which shows the first robot arm 15 in detail. A similar situation can be found at the second robot arm 21.

The first and second slag trajectory 51 , 54 are shown in figure 33, which shows a side view of the interconnected first and second pipe section 4, 5 in the direction of the second

longitudinal axis 9. The first slag trajectory 51 extends from a left intermediate slag location 55 along a top slag location 52 until a right intermediate slag location 56. The first slag head 49 is during removal of slag moved from the top slag location 52 to the left intermediate slag location 55 and subsequently from the top slag location 52 to the right intermediate slag location 56. The second slag trajectory 54 extends from the left slag weld location along a bottom slag location 53 until the right intermediate slag location 56. The second slag head 50 is during removal of slag moved from the right intermediate slag location 56 to the bottom slag location 53 and subsequently from the left intermediate slag location 55 to the bottom slag location 53. The left intermediate slag location 55 and the right intermediate slag location 56 are located in the horizontal plane extending through the first longitudinal axis 7 of the first pipe section 4. The top slag location 52 is located above and the bottom slag location 53 is located below said horizontal plane. The first and second slag head 50 may be moved one or multiple times along the first and second trajectory to remove slag from the weld layer 36 in the welding groove 2. The first robot arm 15 and the second robot arm 21 place in figure 34 the first slag head 49 and the second slag head 50 back at their storage position to decouple the slag heads from the robot arms. Figure 35 shows an enlarged view of part XXXV of figure 34, which shows the first robot arm 15 in detail. A similar situation can be found at the second robot arm 21.

The first and second robot arm 15, 21 are now free to repeat the cycle of scanning, welding and slag removal until the welding groove 2 is filed with weld layer 36s.

The result thereof is shown in the figures 36-38. The figures 36 and 37 show a view in perspective and a side view of the completely welded first and second pipe section 4, 5.

Figure 8 shows a view in cross section along the second longitudinal axis 9 of the welded first and second pipe section of figure 36. The cycle has been repeated six times, meaning that six weld layers 36 are provided in the welding groove 2 to form the completed weld 62. As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting, but rather, to provide an understandable description of the invention.

The terms "a" or "an", as used herein, are defined as one or more than one. The term plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The terms including and/or having, as used herein, are defined as comprising (i.e., open language, not excluding other elements or steps). Any reference signs in the claims should not be construed as limiting the scope of the claims or the invention.

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

1. Welding system for filling a welding groove of a branch connection between a first pipe section and a second pipe section, wherein the first pipe section comprises a first wall surrounding a first longitudinal axis, the second pipe section comprises a second wall surrounding a second longitudinal axis and a pipe end having an end rim, and a first rim part of the end rim is connected to the first wall and a second rim part of the end rim is located at a distance from the first wall to form the welding groove, said system

comprising;

- a control unit which is in communication connection with the first and second robot arm and the scanner and configured to, on basis of the data provided by the scanner, determine a first welding trajectory for the first welding head to provide a first weld in the welding groove and a second welding trajectory for the second welding head to provide a second weld in the welding groove, wherein the first welding trajectory extends above the horizontal plane, the second welding trajectory extends below the horizontal plane and the first and second weld together form a weld layer which completely surrounds the second longitudinal axis, and wherein the control unit is further configured to repeat said scanning of the welding groove with the scanner and subsequently said welding with the first and second welding head until the welding groove is filled with weld layers.

2. Welding system according to any one of the preceding claims, wherein the first and second robot arm are free from any supporting connection with the first and second pipe section.

3. Welding system according to any one of the preceding claims, wherein welding

system comprises a first driver to move the first mounting base of the first robot arm along a first straight horizontal trajectory and a second driver to move the second mounting base of the second robot arm along a second straight horizontal trajectory.

4. Welding system according to claim 3, wherein the first and second straight horizontal trajectory extend substantially parallel to each other.

5. Welding system according to claim 3 or 4, wherein the support device is configured to support the first and second pipe section with the first longitudinal axis extending substantially parallel to the first straight horizontal trajectory.

6. Welding system according to any one of the claims 3-5, wherein the support device is configured to support the first and second pipe section with the first longitudinal axis extending substantially parallel to the second straight horizontal trajectory.

7. Welding system according to any one of the preceding claims, wherein the first

welding trajectory extends over more than 50 % of the welding groove and the second welding trajectory extends over less than 50 % of the welding groove.

8. Welding system according to any one of the claims 1-6, wherein the first welding

trajectory extends between 55-75 % of the welding groove and the second welding trajectory extends over 25-45 % of the welding groove.

9. Welding system according to any one of the claims 1-6, wherein the first welding

trajectory extends over around 60 % of the welding groove and the second welding trajectory extends around over 40 % of the welding groove.

10. Welding system according to any one of the claims 7-9, wherein the first welding

trajectory also extends along part of the welding groove located below the horizontal plane and the second welding trajectory only extends along part of the welding groove located below the horizontal plane.

1 1. Welding system according to any one of the preceding claims, wherein;

- the scanner comprises a first scan head and a second scan head,

- the control unit is configured to move the first scan head with the first robot arm along a first scan trajectory extending along the welding groove and above the horizontal plane and configured to move the second scan head with the second robot arm along a second scan trajectory extending along the welding groove and below the horizontal plane in order to scan the welding groove, wherein the first and second scan trajectory together completely surround the second longitudinal axis.

12. Welding system according to any one of the preceding claims, wherein the first

welding trajectory differs from the first scan trajectory and the second welding trajectory differs from the second scan trajectory.

13. Welding system according to any one of the preceding claims, wherein the control unit is configured to optimise the first welding trajectory on basis of welding

characteristics of the first welding head and the second welding trajectory on basis of welding characteristics of the second welding head.

14. Welding system according to any one of the preceding claims, wherein the control unit is configured to optimise the first scan trajectory on basis of scanning characteristics of the first scan head and the second scan trajectory on basis of scan characteristics of the second scan head.

15. Welding system according to any one of the preceding claims, wherein;

16. Welding system according to any one of the preceding claims, wherein the control unit is configured to after the weld layer is provided in the welding groove by the first and second welding head, remove slag from said weld layer with the first and second slag head.

17. Welding system according to any one of the preceding claims, wherein the first

welding trajectory is equal to the first slag trajectory and the second welding trajectory is equal to the second slag trajectory.

18. Welding system according to any one of the claims 1-16, wherein the first welding trajectory differs from the first slag trajectory and the second welding trajectory differs from the second slag trajectory.

19. Welding system according to any one of the preceding claims, wherein the control unit is configured to optimise the first slag trajectory on basis of the slag removal characteristics of the first scan head and the second slag trajectory on basis of slag characteristics of the second scan head.

20. Welding system according to any one of the preceding claims, wherein the first and second robot arm are each configured to move the first and second welding head, respectively, with at least 6 degrees of freedom.

21. Welding system according to any one of the preceding claims, wherein the control unit is configured to control the system in order to;

- provide the weld layer by operatively coupling the first welding head to the first robot arm and operatively coupling the second welding head to the second robot arm, subsequently providing the first weld with the first welding head and providing the second weld with the second welding head, and subsequently decoupling the first welding head from the first robot arm and decoupling the second welding head from the second robot arm.

22. Welding system according to any one of the preceding claims, wherein the control unit is configured to control the system in order to, after decoupling the first welding head from the first robot arm and decoupling the second welding head from the second robot arm, operatively coupling the first slag head to the first robot arm and operatively coupling the second slag head to the second robot arm, subsequently removing slag from the complete weld layer with the first slag head and the second slag head, and subsequently decoupling the first slag head from the first robot arm decoupling the second slag head from the second robot arm.

23. Welding system according to any one of the preceding claims, wherein the first

support frame and the second support frame are formed by a single support frame.

24. Method of filling a welding groove of a branch connection between a first pipe section and a second pipe section, wherein the first pipe section comprises a first wall surrounding a first longitudinal axis, the second pipe section comprises a second wall surrounding a second longitudinal axis and a pipe end having an end rim, and a first rim part of the end rim is connected to the first wall and a second rim part of the end rim is located at a distance from the first wall to form the welding groove, said method comprising the steps of;

25. Method according to claim 24, wherein;

- the scanning of the welding groove comprises operatively coupling the first scan head to the first robot arm and operatively coupling the second scan head to the second robot arm, subsequently moving the first scan head along the first scan trajectory and moving the second scan head along the second scan trajectory in order to scan the complete welding groove, and subsequently decoupling the first scan head from the first robot arm and decoupling the second scan head from the second robot arm, and

26. Method according to claim 24 or 25, wherein the providing of the weld layer

comprises, after decoupling the first welding head from the first robot arm and decoupling the second welding head from the second robot arm, performing the steps of operatively coupling the first slag head to the first robot arm and operatively coupling the second slag head to the second robot arm, subsequently moving the first slag head along the first slag trajectory and moving the second slag head along the second slag trajectory in order to remove slag from the complete weld layer, and subsequently decoupling the first slag head from the first robot arm decoupling the second slag head from the second robot arm.