Apparatus and method for lined pipe welding

1. A joining sleeve configured to connect internal liners of two internally lined pipe sections across a welded pipe section joint, the joining sleeve comprising:

a sleeve body having a first end and a second end, the first and second ends configured to couple with opposing ends of first and second internal liners respectively; and

a collar disposed around and radially outward of an outer surface of the sleeve body, the collar having a first retracted condition in which it has a first outer diameter, and a second expanded condition in which it has a second outer diameter, larger than the first outer diameter, wherein the collar is configured to protect the sleeve body and the first and second internal liners during a welding operation to form the weld pipe section joint;

wherein the collar comprises a split ring comprising respective ends which overlap in a circumferential direction of the collar; and

wherein a gap is produced between the outer surface of the joining sleeve body and the inner surface of the collar when the collar is in its second, expanded condition.

2. The joining sleeve according to claim 1 , wherein the joining sleeve comprises an insulating layer which comprises a layer of thermally insulating material disposed around at least a portion of the outer surface of the sleeve body, and wherein the collar at least partially overlays the insulating layer.

3. The joining sleeve according to claim 1 , wherein the collar comprises a joggled section of material such that a first end section of the collar is radially offset with respect to a second end section of the collar.

4. The joining sleeve according to claim 1 , wherein the collar is biased towards its second, expanded condition.

5. The joining sleeve according to claim 1 , wherein the first outer diameter of the collar is smaller than an inner diameter of the pipe sections, such that the collar does not come in to substantial contact with inner surfaces of the pipe sections in its first retracted condition.

6. The joining sleeve according to claim 1 , wherein the collar has a state of equilibrium in which it has a diameter which is greater than the inner diameter of the pipe sections, such that the collar exerts a force on the inner surfaces of the pipe sections when it is in its second, expanded condition.

7. The joining sleeve according to claim 1 , wherein the collar comprises at least one formation.

8. The joining sleeve according to claim 7 , wherein at least one formation is configured to engage respective ends of the split ring collar together.

9. The joining sleeve according to claim 8 , wherein an outer surface of the at least one formation is configured to locate in an inner surface of the at least one formation at the overlap of collar material.

10. The joining sleeve according to claim 7 , wherein the at least one formation is configured to come into contact with the inner surfaces of the pipe sections when the collar is in its second, expanded condition, such that a gap is present between the outer surface of the collar and the inner surfaces of the pipe sections.

11. The joining sleeve according to claim 7 , wherein the at least one formation comprises a groove.

12. The joining sleeve according to claim 11 , wherein the groove is a continuous groove on a surface of the collar, and wherein an outer surface of the groove of a first end of the respective ends of the collar is configured to locate in an inner surface of the groove of a second end of the respective ends of the collar.

13. The joining sleeve according to claim 1 , comprising a retaining device configured to retain the collar in its first, retracted condition, the retaining device being actuable and/or releasable to enable the collar to move to its second, expanded condition.

14. The joining sleeve according to claim 13 , wherein the retaining device is configured to be actuated and/or released actively prior to a welding operation.

15. The joining sleeve according to claim 13 , wherein the retaining device is configured to be actuated and/or released passively during a welding operation.

16. The joining sleeve according to claim 13 , wherein the retaining device is provided with at least one protruding member which is arranged to abut the ends of the two pipe sections and project from a gap therebetween.

17. The joining sleeve according to claim 1 , comprising a protective film disposed over the sleeve body and/or the collar, wherein the protective film is configured to be broken, ruptured or removed during a welding operation.

18. The joining sleeve according to claim 1 , wherein the collar comprises a layer of insulation on an outer surface of a collar.

19. A method for connecting the internal liners of two internally lined pipe sections in a pipe welding operation, the method comprising:

providing a joining sleeve having a sleeve body and a collar configured to protect the sleeve body and internal liners of the pipe sections during the pipe welding operation positioned around and radially outward of an outer surface of the sleeve body, the collar comprising a split ring comprising respective ends which overlap in a circumferential direction of the collar, and the collar being in a first retracted condition having a first outer diameter;

locating the joining sleeve in a pipe section joint, such that first and second ends of the sleeve body couple with opposing ends of first and second internal liners respectively, and such that the collar is disposed proximate the weld location;

causing the collar to move to a second expanded condition in which it has a second outer diameter, larger than the first outer diameter;

wherein a gap is produced between the outer surface of the joining sleeve body and the inner surface of the collar when the collar is in its second, expanded condition.

20. The method according to claim 19 , wherein the joining sleeve further comprises a retaining device which is configured to retain the collar in its first, retracted condition and which is actuable and/or releasable to enable the collar to move to its second, expanded condition, and wherein the method comprises actuating and/or releasing the retaining device to allow the collar to move to its second, expanded condition.

21. A pipeline comprising two internally lined pipe sections joined by a welded pipe section joint, and a joining sleeve according to claim 1 connecting first and second internal liners of the respective pipe sections.

22. A collar for a joining sleeve, the joining sleeve comprising a sleeve body having a first end and a second end, the first and second ends configured to couple with opposing ends of first and second internal liners respectively to connect two internally lined pipe sections across a welded pipe section joint;

wherein the collar is configured to be disposed around and radially outward of an outer surface of the sleeve body and protect the sleeve body and the first and second internal liners during a welding operation to form the welded pipe section joint;

wherein the collar has a first retracted condition in which it has a first outer diameter, and a second expanded condition in which it has a second outer diameter, larger than the first outer diameter;

wherein the collar comprises a split ring comprising respective ends which overlap in a circumferential direction of the collar; and

wherein a gap is produced between the outer surface of the joining sleeve body and the inner surface of the collar when the collar is in its second, expanded condition.