GB2589267A

GB2589267A - A pipe cutting tool

Info

Publication number: GB2589267A
Application number: GB2100793.5A
Authority: GB
Inventors: Andrew Wibberley Scott
Original assignee: Peak Pipe Systems Ltd
Current assignee: Peak Pipe Systems Ltd
Priority date: 2016-10-28
Filing date: 2016-10-28
Publication date: 2021-05-26
Also published as: GB202100793D0

Abstract

A cutting tool 31 for machining a welding profile of a pipe comprises a substantially ring-shaped body 32, including one or more castellations 38, each castellation comprises a cutting profile formed in its outside circumferential wall, wherein the cutting profile includes a first surface 35 adjacent an end face 41 of the body and radially outward second surface 36; wherein the cutting profile is arranged so that the first surface extends axially relative to the cutting tool to transition between an end face of the cutting tool and the radially outward second surface; wherein the second surface of the cutting profile comprises a curved cross section. Each castellation may have a leading surface 40 and a trailing surface 34 and the first surface may have a chamfer. A third surface 39 may be provided adjacent the second surface.

Description

A PIPE CUTTING TOOL Technical Field of the Invention The present invention relates to a pipe cutting tool suitable for a pipe arranged to reduce interaction between a weld bead formed when a pipeline is made from lengths of the pipe and the substance carried in the pipe. A method of installing the pipe and a pipe fitting are also disclosed.

Background to the Invention

Butt welding (or heat fusion or heat welding) is a process used to join together two different pieces of a thermoplastic together. It is a common technique used in forming a plastic pipework, particularly in joining a first length of pipe to a second length a pipe. The process involves heating and softening an end of both lengths of pipe by using a hot plate and then pressing heated ends of the pipes together. When the heated pipe ends cool, a permanent bond is formed between the lengths of pipe.

Pressing the lengths of pipe together can cause a bead of softened thermoplastic to be pushed so as to protrude beyond the inside diameter of the joined pipes, which can impede fluid flow through the pipes or damage wiring or material in the pipe.

Figure 1 shows a wall of a first length of pipe 1 and a second length of a pipe 2 that have been joined together with a conventional butt weld. As can be seen, an internal bead of thermoplastic 3 and an external bead of thermoplastic 4 have been formed adjacent the join 5 during the welding process. These beads 3, 4 are problematic for the above reasons. As such, the beads 3, 4 are typically removed from the pipe after it has been formed by, for example, cutting the beads 3, 4 from the pipe. This slows down installation and also results in increased installation costs.

Embodiments of the present invention seek to address the above problems. Summary of the Invention According to a first aspect of the present invention, there is provided a cutting tool for machining the welding profile comprising a first surface and a radially outward second surface comprising a groove for accommodating a weld bead formed during a welding process, wherein the welding profile is arranged so that the first surface is adjacent an inside surface of the pipe wall and extends axially relative to the pipe to transition between the inside surface of the pipe wall and the radially outward surface at the first end region of a pipe, the cutting tool comprising a substantially ring-shaped body with one or more castellations; wherein each castellation comprises a cutting profile formed in its outside circumferential wall, wherein the cutting profile includes a first surface adjacent an end face of the body and radially outward second surface; wherein the cutting profile is arranged so that the first surface extends axially relative to the cutting tool to transition between an end face of the cutting tool and the radially outward second surface; wherein the second surface of the cutting profile comprises a curved cross section.

The body may comprise an aperture positioned towards its centre.

The body may comprise a plurality of castellations. Each castellations may be arranged on an outside circumferential wall of the body.

Each castellation may comprise a leading surface and a trailing surface. A cutting edge may be formed in each castellation between the leading surface and the cutting profile. The leading surface of each castellation may be taller than the trailing surface.

The first surface of the cutting profile may comprise a chamfer that transitions from the radially inner end face of the cutting tool to the radially outer second surface of the cutting profile.

The second surface may comprise a quarter circle cross-section. The second surface may transition from the first surface of the cutting profile away from the first surface.

The cutting profile may comprise a third surface adjacent the second surface. The third surface may be adjacent an end face of the cutting tool. The third surface may transition between the second surface and an end face of the cutting tool.

According to a first example there is provided a pipe comprising: a first end region; and a welding profile machined at the first end region, the welding profile comprising a first surface and a radially outward second surface forming a groove for accommodating a weld bead formed during a welding process, wherein the welding profile is arranged so that the first surface is adjacent an inside surface of the pipe wall IS and extends axially relative to the pipe to transition between the inside surface of the pipe wall and the radially outward second surface.

In this way, if, during a welding process, a weld bead is formed that protrudes radially internally, the second surface of the welding profile receives and houses the internal weld bead so that it need not protrude into the pipe and beyond the first surface and therefore interact significantly with material that is inside the pipe, such as a cable or a fluid. The present invention is particularly useful in avoiding damage to insulation on wiring that is pulled through the pipe. This arrangement provides the advantage that no additional steps are required to remove the internal weld bead after the welding process, which reduces installation costs and time. In addition, the first surface reduces the risk of the weld bead accommodated in the groove of the second surface damaging insulation on cables or wiring that are pulled through the pipe.

The pipe may be cylindrical. The pipe may have a circular cross-section, a rectangular cross-section, a square cross-section or an elliptical cross section.

The first end region may comprise a first end face disposed at the distal end (or free end) of the first end region. The pipe may comprise a second end region disposed axially distal to the first end region. The second end region may comprise a second end face disposed at the distal end of the second end region. The pipe may comprise a welding profile machined at the second end region.

The welding profile may be machined into or onto the wall of the pipe.

The welding profile may be machined in or on the first end face and/or the second end face.

The machining of the welding profile may be a process such as cutting or foil ling.

The first surface of the welding profile may comprise a chamfer that transitions from the radially inner inside surface of the pipe wall to the radially outer second surface of the welding profile. The first surface may form a substantially frustoconical surface. A distal end of the first surface may extend radially outwards, relative to the pipe, from a proximal end that is adjacent or connected to the inside surface of the pipe wall. The first surface may recess the second surface into the pipe wall. The first surface may be arranged so that it is not oriented parallel to or perpendicular to the axial axis of the pipe. The first surface may have a varying radius relative to the pipe. The first surface may be oriented substantially diagonally relative to the axial axis of the pipe. The first surface may be flat. The first surface may comprise a straight cross-section. The first surface may be convex. The first surface may comprise a curved cross section. In this way, by providing a smooth transition between the recessed second surface of the welding profile and the pipe wall, the first surface helps to mitigate the risk of the pipe, or a weld between pipes, damaging insulation on cables or wiring that are subsequently pulled through the pipe.

The second surface of the welding profile may comprise a curved cross section. The second surface may comprise a quarter circle cross-section. The second surface may have a concave radiussed shape. The concave radius may be arranged to face away from the first surface. The second surface may comprise a flat cross-section. The second surface may comprise step. The second surface may transition from the first surface of the welding profile towards a free end of the pipe. The second surface may transition, for example, to a first end face or to a further surface of the welding profile. A distal end of the second surface may be spaced radially outwardly from the first surface, relative to the axial axis of the pipe, from a proximal end that is adjacent or connected to the first surface. The second surface may have a varying radius relative to the pipe.

The welding profile may comprise a third surface adjacent the second surface. The third surface may be adjacent an end face of the pipe, such as the first end face. The third surface may transition between the second surface and an end face of the pipe, such as the first end face. The third surface may have a constant radius relative to the pipe. The third surface may be flat.

The pipe may be formed from a polymer. In particular, the pipe may be formed from a thermoplastic. Specifically, the pipe may be formed from polyethylene.

The pipe may be formed or extruded from one or more coloured polymers. In particular, the pipe may be formed from a radially inner first coloured polymer and a radially outer second coloured polymer. The first coloured polymer may be coloured black. The second coloured polymer may be of a second colour. In this way, the pipe is formed with colouring that may indicate that the pipe comprises the welding profile described above.

According to a second example there is provided a method of making a pipeline, the method comprising the step of: machining a welding profile according to the first aspect of the invention at a first end region of a first length of pipe.

The welding profile may be cut into the first end region of the first length of pipe. The welding profile may be formed on the first end region of the first length of pipe.

The method may further comprise the step of: butt welding the first end region of the first length of pipe to a first end region of a second length of pipe. The butt welding process may comprise the steps of: heating apart of each first end region, such as the end face, using a heating means and pressing the heated parts of the lengths of pipe together.

The method may further comprise the step of: machining a welding profile according to the first aspect of the invention into or onto a first end region of a second length of pipe.

The method may further comprise the step of: forming the first length of pipe from a polymer. The polymer may be thermoplastic. The first length of pipe may be formed by a conventional process known in the art.

The method may further commise the step of: forming the second length of pipe from a polymer. The polymer may be thermoplastic. The second length of pipe may he formed by a conventional process known in the art.

The method may further comprise the step of transporting the formed first length of pipe and/or the formed second length of pipe to a site where the pipeline is to be installed. The length of lengths of pipe may be transported before machining the first or second end region of the length or lengths of pipe.

The method of the second example may incorporate any or all features of the first example as desired or as appropriate.

According to a third example, there is provided a pipe fitting comprising: a first end region; and a welding profile machined at the first end region, the welding profile comprising a first surface and a radially outward second surface forming a groove for accommodating a weld bead formed during a welding process, wherein the welding profile is arranged so that the first surface is adjacent an inside surface of the pipe fitting wall and extends axially relative to the pipe fitting to transition between the inside surface of the pipe wall and the radially outward second surface.

The pipe fitting of the third example may incorporate any or all features of the first example as desired or as appropriate.

According to a fourth example, there is provided a pipe comprising: a first end region; and a welding profile machined at the first end region, the welding profile comprising a radially outward second surface forming a groove for accommodating a weld bead formed during a welding process.

The pipe of the fourth example may incorporate any or all features of the first example as desired or as appropriate.

Detailed Description of the Invention

In order that the invention may be more clearly understood embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, of which: Figure 1 is a cross section view of butt weld between two conventional lengths of pipe; Figure 2 is a perspective view of a length of pipe; Figure 3 is a cross section view of the end of the length of pipe shown in Figure 2; Figure 4 is a close up of a cross section view of part of the end of the length of pipe shown in Figures 2 and 3; Figure 5 is a cross section view of a butt weld between two of the lengths of pipe shown in Figures 2-4; and Figure 6 is a cutting tool, which is used in fon ling the length of pipe shown in Figures 2-4.

Figure 1 shows a butt weld that joins two conventional lengths of pipe 1, 2 together and is discussed in the -Background to the Invention" above.

Referring to Figures 2-4, a length of substantially cylindrical pipe 11 comprises a body 25 having a first end region 12 and a second end region 17, defining an axially extending bore 20. The bore 20 may be used to, for example, carry cables or wiring, or convey a fluid. The body 25 comprises a wall 18 having an inside surface 21 and an outside surface 19. The pipe 11 is formed from a thermoplastic such as polyethylene and therefore the pipe becomes mouldable when heated. The first end region 12 is arranged for butt welding to a similar end region on another length of pipe.

The first end region 12 comprises a flat first end face 13 at a distal end of the pipe 11. The first end face 13 is arranged so that it is oriented substantially perpendicular to the pipe wall 18.

A welding profile in the form of a cut-out 22 is machined or cut into the first end region 12 of the pipe 11 adjacent the first end face 13 by using the cutting tool 31 illustrated in Figure 6. The cut-out 22 increases the diameter of the bore 20 at the first end region 12. The cut-out 22 comprises a first surface 14 adjacent and extending axially from the inside surface 21 of the pipe wall 18, a third surface 16 adjacent and extending axially from the end face 13 of the pipe 11, and a second surface 15 extending axially from the first surface 14 to the third surface 16.

The first surface 14 is a flat section formed as a chamfer between the radially outer second surface 15 (relative to the bore 20 of the pipe 11) and the radially inner (relative to the first surface 14) inside surface 21 of the pipe wall 18. The first surface 14 extends axially relative to the pipe 11 between the pipe wall 18 and the first surface 14 to connect them together.

The third surface 16 extends axially relative to the pipe 11 between the second surface 15 and the first end face 13. The third surface 16 is formed with a straight cross section that it is substantially parallel to the inside surface 21 and the outside surface 19 of the pipe wall 18, and therefore substantially perpendicular to the first end face 13. The third surface 16 is the section of the first end region 12 of the pipe 11 that is heated by a hot plate during a butt welding process and is thus the section that may form one or more weld beads, as is described below. The third surface 16 has a diameter that is larger than the diameter of the bore 20.

The second surface 15 has a curved cross section that curves radially outwardly from the first surface 14 to the third surface 16, relative to the bore 20 of the pipe 11. The concave radius of the second surface 15 faces away from the first surface 14 and towards the first end face 13, and forms a pocket in the first end region 11. The second surface extends axially relative to the pipe 11 between the first surface 14 and the third surface 16. The second surface 15 thus fonts a groove in the inside surface 21 of the pipe wall 18.

Referring to Figure 5, a weld between a first length of pipe 11 according to an embodiment of the invention and a second length of pipe 51 according to an embodiment of the invention is shown. The method of welding the lengths of pipe 11, 51 together is described below. The welding process has formed an external weld bead 23 and an internal weld bead 24. The external weld bead 23 protrudes above the outside surface 19 of the pipe wall 18 and can be cut off and removed from the join between the pipes 11, 51 by a knife of the like. As is discussed below, the internal weld bead 24 is housed substantially within the grooves of the second surfaces 15 of the lengths of pipe 11, 51, which have joined together to form a pocket. In addition, the pocket formed by the combined second surfaces 15 is recessed into the pipe walls 18 by the chamfer of the first surfaces 14. The internal weld bead 24 therefore does not protrude beyond the inside 1 I surface 21 of the pipe wall 18 and so does not substantially interact with or affect the substance that is inside the lengths of pipe 11, 51.

Referring to Figure 6, a cutting tool 31 for machining a welding profile in form of the cut-out 22 into the length pipe 11 is shown. The cutting tool 31 comprises a substantially ring-shaped body 32 with a central aperture 33 extending between a first end face 41 and a second end face (not shown). The first end face 41 and the second end face are substantially parallel with one another. The body 32 comprises a plurality of castellations 38 that have been formed by cutting a series of radial grooves 37 into the outside circumferential wall of the body 32 of the cutting tool 31. The grooves are cut into the body 32 such that each castellation 38 is formed with a leading surface 40 and a trailing surface 34. The leading surface 40 and the trailing surface 34 of each castellation are oriented substantially parallel to one another and are angled relative to the radial axis of the body 32, which thus angles each castellation relative to the radial axis of body 32.

A cutting profile is cut into the outside circumferential wall of each castellation 38. The cutting profile comprises a first surface 35 adjacent the second end face of the body 32, a third surface 39 adjacent the first end face 41, and a second surface 36 extending between the first surface 35 and the third surface 39. A cutting edge 42 is formed at the border between the leading surface 40 of each castellation 38 and the cutting profile. The leading surface 40 of each castellation 38 is taller than the (railing surface 34 so that the cutting profile slopes radially outwardly from the trailing surface 34 to the leading surface 40.

Each first surface 35 has a straight cross section and acts a chamfer extending between a second surface 36 and the first end face 41 of the body 32. Each first surface of a castellation 38 is formed radially inward of the second surface 36. Each first surface 35 extends axially from the first end face 41 to a second surface 36.

Each second surface 36 is a curved section formed so that it curves radially outwardly from the first surface 35 to the third surface 39. Each second surface 36 of a castellation 38 is also formed radially inward of the third surface 39 and extends axially between a first surface 34 and a third surface 39.

Each third surface 39 has a straight cross section formed so that it is substantially perpendicular to the first end face 41 and the second end face. Each third surface 39 extends axially between a second surface 36 and the second end face.

The cutting tool 31 is therefore arranged such that it can machine the welding profile shown in Figure 2-4 into the end region of a length of pipe 11.

A method of butt welding together a first length of the pipe 11 shown in Figures 2-4 and a second length of pipe 51 to form a pipeline will now be described. The second length of pipe 51 is identical to the first length of pipe 11.

The two lengths of pipe 11, 51 are formed using a conventional pipe forming process that is well known in the art. The lengths of pipe 11, 51 are then transported to a work site.

A welding profile in the form of a cut-out 22 as described above is then machined into the first end region 12 of each length of pipe 11, 51 using the cutting tool 31 shown in Figure 6. The cutting tool 31 is attached to suitable machine such as a router or a drill so that it can be rotated about its central aperture 33. The cutting tool 31 rotates radially in the direction of its cutting edges 42 (i.e. anti-clockwise in Figure 6). The cutting tool 31 and the lengths of pipe 11, 51 are moved relative to one another so that the cutting profile of the cutting tool 31 cuts the welding profile into the inside surface 21 of the pipe wall 18. In particular, the cutting tool 31 is held in a stationary position whilst activated and the inside surface 21 of the pipe wall 18 of each length of pipe 11, 51 is contacted with the cutting tool 31 and then rotated whilst held in contact with the cutting tool 31.

A heating means such as a hot plate is used to increase the temperature of the end face 13 of each length of pipe 11, 51, which also increases the temperature of the adjacent third surface 16. When the end face 13 and third surface 16 reach a sufficiently high temperature (which is dependent on the material the pipe has been formed from) the end face 13 and the third surface 16 become soft and plastically mouldable,. The remaining parts of the lengths of pipe 11, 51, such as the first and second surfaces 14, 15 do not reach a sufficiently high temperature to become soft and mouldable.

The two lengths of pipe 11, 51 are removed from the hot plate, arranged so that their machined first end regions 12 are adjacent and aligned with one another, and then pressed together so that the end faces 13 come into contact. This contact between the mouldable end faces13 begins to bond them together to form a pipeline.

The lengths of pipe 11, 51 are urged together until the second surfaces 15, which have not been heated enough to be mouldable, are in contact, or almost in contact. This forces the soft, mouldable thermoplastic material to deform radially inwardly and outwardly, relative to the walls 18 of the lengths of pipe 11, 51.

The thermoplastic material that is forced to deform radially outwardly creates an external weld bead 23 that protrudes above the outside surface 19 of the wall 18 of each length of pipe 11, 51. The external weld bead 23 can help to bond the lengths of pipe 11, 51 together, but it can also he cut off and removed if required, for aesthetic and/or practical reasons.

The thermoplastic material that is forced to deform radially inwardly creates an internal weld bead 24 that is received into and accommodated by a pocket formed by the curved second surfaces 15 of the lengths of pipe 11, 51 connecting together during the welding process. As shown in Figure 5, the internal weld bead 24 does not therefore protrude below the inside surface 21 of the wall 18 and into the bore 20.

The temperature to which the end face 13 of each length of pipe 11, 51 is heated to and the pressure applied to the heated lengths of pipe 11, 51 to force them together are I 0 chosen to ensure that the internal weld bead 24 formed during the above welding process does not intrude into the bore 20 of the pipes 11, 51.

The size and the curved shape of the groove of the second surfaces 15 of the cutout 22 forms a pocket that is shaped to encourage formation of an internal weld bead 24 and yet ensure that the internal weld bead 24 fills up most or all of the pocket rather than IS being pushed further radially inwardly towards the bore 20. In addition, this size and shape also helps to ensure that the internal bead weld 24 does not contact substantially with the first surfaces 14 that connect the second surfaces 15 to the inside surface 21 of the pipe wall 18.

With this arrangement, the internal weld bead 24 is accommodated within the pocket formed by the second surfaces 15 of the lengths of pipe 11, 51 linking together so that the internal weld bead 24 cannot protrude into the pipe. The first surfaces 14 also reduce the risk of the internal weld bead 24 accommodated in the pocket damaging insulation on cables or wiring that are pulled through the pipeline formed by the lengths of pipe 11, 51 joined together.

The above embodiments are described by way of example only. Many variations are possible without departing from the scope of the invention as defined in the appended claims.

For example, instead of being cut into the first end region 11, the welding profile may be formed on or moulded on the pipe 11, either integrally or as a separate part.

Certain definitions of the invention are set out in the following numbered 10 paragraphs:

PARAGRAPHS

1. A pipe comprising: a first end region; and a welding profile machined at the first end region, the welding profile comprising a first surface and a radially outward second surface comprising a groove for accommodating a weld bead formed during a welding process, wherein the welding profile is arranged so that the first surface is adjacent an inside surface of the pipe wall and extends axially relative to the pipe to transition between the inside surface of the pipe wall and the radially outward second surface.

2. A pipe according to PARAGRAPH 1, wherein the pipe is cylindrical.

3. A pipe according to PARAGRAPH 2, wherein the pipe has a circular cross-section.

4. A pipe according to any of PARAGRAPHS 1-3, wherein the first end region comprises a first end face disposed at the distal end of the first end region.

A pipe according to any of PARAGRAPHS 1-4, further comprising a second end region disposed axially distal to the first end region.

6. A pipe according to PARAGRAPH 5, further comprising a welding profile machined at the second end region.

7. A pipe according to any of PARAGRAPHS 1-6, wherein the first surface of the welding profile comprises a chamfer that transitions from the radially inner inside surface of the pipe wall to the radially outer second surface of the welding profile.

8. A pipe according to any of PARAGRAPHS 1-7, wherein the first surface forms a substantially frustoconical surface.

A pipe according to any of PARAGRAPHS 1-8, wherein a distal end of the first surface extends radially outwards, relative to the pipe, from a proximal end that is adjacent or connected to the inside surface of the pipe wall.

10. A pipe according to any of PARAGRAPHS 1-9, wherein the first surface is arranged so that it is not oriented parallel to or perpendicular to the axial axis of the pipe.

11. A pipe according to any of PARAGRAPHS 1-10, wherein the first surface is flat.

12. A pipe according to any of PARAGRAPHS 1-10, wherein the first surface is convex.

13. A pipe according to any of PARAGRAPHS 1-12, wherein the second surface of the welding profile comprises a curved cross section.

14. A pipe according to PARAGRAPH 13, wherein the second surface comprises a quarter circle cross-section.

15. A pipe according to PARAGRAPH 13, wherein the second surface has a concave radiussed shape.

16. A pipe according to PARAGRAPH 15, wherein the concave radius is arranged to face away from the first surface.

17. A pipe according to any of PARAGRAPHS 1-16, wherein the second surface transitions from the first surface of the welding profile towards a free end of the pipe.

18. A pipe according to any of PARAGRAPHS 1-17, wherein the second surface transitions to a first end face a further surface of the welding profile.

19. A pipe according to any of PARAGRAPHS 1-18, wherein a distal end of the second surface is spaced radially outwardly from the first surface, relative to the axial axis of the pipe, from a proximal end that is adjacent or connected to the first surface.

20. A pipe according to any of PARAGRAPHS 1-19, wherein the welding profile may comprise a third surface adjacent the second surface.

21. A pipe according to PARAGRAPH 20 when dependent on PARAGRAPH 4, wherein the third surface is adjacent the first end face of the pipe.

22. A pipe according to PARAGRAPH 21, wherein the third surface transitions between the second surface and the first end face of the pipe.

23. A pipe according to any one of PARAGRAPHS 20-22, wherein the third surface is flat.

24. A pipe according to any of PARAGRAPHS 1-23, wherein the pipe is formed from a polymer.

25. A pipe according to PARAGRAPH 24, wherein the pipe is formed from a thermoplastic.

26. A pipe according to PARAGRAPH 24 or PARAGRAPH 25, wherein the pipe is formed or extruded from one or more coloured polymers.

27. A pipe according to PARAGRAPH 26, wherein the pipe is formed from a radially inner first coloured polymer and a radially outer second coloured polymer.

28. A pipe according to PARAGRAPH 27, wherein the first coloured polymer is coloured hlack.

29. A pipe according to PARAGRAPH 27 or PARAGRAPH 28, wherein the second coloured polymer is coloured pink.

30. A method of making a pipeline, the method comprising the step of: machining a welding profile according to any one of PARAGRAPHS 1-29 at a first end region of a first length of pipe.

31. A method according to PARAGRAPH 30, wherein the welding profile is cut into the first end region of the first length of pipe.

32. A method according to PARAGRAPH 30, wherein the welding profile is formed on the first end region of the first length of pipe.

33. A method according to any one of PARAGRAPHS 30-32, further comprising the step of: butt welding the first end region of the first length of pipe to a first end region of a second length of pipe.

34. A method according to PARAGRAPH 33, wherein the butt welding process may comprise the steps of: heating a part of each first end region using a heating means and pressing the heated parts of the lengths of pipe together.

35. A method according to any one of PARAGRAPHS 30-34, further comprising the step of: machining a welding profile according to the first aspect of the invention into or onto a first end region of a second length of pipe.

36. A method according to any one of PARAGRAPHS 30-35. further comprising the step of: forming the first length of pipe from a polymer.

37. A method according to PARAGRAPH 36, wherein the polymer is a thermoplastic.

38. A method according to any one of PARAGRAPHS 30-37, further comprising the step of: forming the second length of pipe from a polymer.

39. A method according to PARAGRAPH 38, wherein the polymer is a thermoplastic.

40. A method according to any one of PARAGRAPHS 30-39, may further comprising the step of transporting the formed first length of pipe and/or the formed second length of pipe to a site where the pipeline is to be installed.

41. A cutting tool for machining the welding profile of any one of PARAGRAPHS 1- 29 at the first end region of a pipe.

42. A cutting tool according to PARAGRAPH 41, further comprising a body.

43. A cutting tool according to PARAGRAPH 42, wherein the body is substantially ring-shaped.

44. A cutting tool according to PARAGRAPH 42 or PARAGRAPH 43, wherein the body comprises one or more castellations.

45. A cutting tool according to PARAGRAPH 44. wherein the body comprises a plurality of castellations.

46. A cutting tool according to PARAGRAPH 44 or PARAGRAPH 45, wherein each castellation is arranged on an outside circumferential wall of the body.

47. A cutting tool according to any one of PARAGRAPHS 44-46, wherein each castellation comprises a cutting profile formed in its outside circumferential wall.

48. A cutting tool according to PARAGRAPH 47. wherein each castellation comprises a leading surface and a trailing surface.

49. A cutting tool according to PARAGRAPH 48, wherein the leading surface of each castellation is taller than the trailing surface.

50. A cutting tool according to PARAGRAPH 48 or PARAGRAPH 49, wherein a cutting edge is formed in each castellation between the leading surface and the cutting profile.

51. A cutting tool according to any one of PARAGRAPHS 47-50, wherein the cutting profile comprises a first surface adjacent an end face of the body, and a radially outward second surface.

52. A cutting tool according to PARAGRAPH 51, wherein the cutting profile is arranged so that the first surface extends axially relative to the cutting tool to transition between an end face of the cutting tool and the radially outward second surface.

53. A cutting tool according to PARAGRAPH 51 or PARAGRAPH 52, wherein the first surface of the cutting profile comprises a chamfer that transitions from the radially inner end face of the cutting tool to the radially outer second surface of the cutting profile.

54. A cutting tool according to any one of PARAGRAPHS 51-53, wherein the second surface of the cutting profile comprises a curved cross section.

55. A cutting tool according to any one of PARAGRAPHS 51-54, wherein the cutting profile comprises a third surface adjacent the second surface.

56. A cutting tool according to PARAGRAPH 55, wherein the third surface transitions between the second surface and an end face of the cutting tool.

57. A pipe fitting comprising: a firs( end region; and a welding profile machined at.

the first end region, the welding profile comprising a first surface and a radially outward second surface forming a groove for accommodating a weld bead formed during a welding process, wherein the welding profile is arranged so that the first surface is adjacent an inside surface of the pipe fitting wall and extends axially relative to the pipe fitting to transition between the inside surface of the pipe wall and the radially outward second surface.

58. A pipe comprising: a first end region; and a welding profile machined at the first end region, the welding profile comprising a radially outward second surface forming a groove for accommodating a weld bead formed during a welding process.

Claims

CLAIMS1. A cutting tool for machining the welding profile comprising a first surface and a radially outward second surface comprising a groove for accommodating a weld bead formed during a welding process, wherein the welding profile is arranged so that the first surface is adjacent an inside surface of the pipe wall and extends axially relative to the pipe to transition between the inside surface of the pipe wall and the radially outward surface at the first end region of a pipe, the cutting tool comprising a substantially ring-shaped body with one or more castellations; wherein each castellation comprises a cutting profile formed in its outside circumferential wall, wherein the cutting profile includes a first surface adjacent an end face of the body and radially outward second surface; wherein the cutting profile is arranged so that the first surface extends axially relative to the cutting tool to transition between an end face of the cutting tool and the radially outward second surface; wherein the second surface of the cutting profile comprises a curved cross section.
2. A cutting tool according to claim 1, wherein the body comprises a plurality of castellations.
3. A cutting tool according to claim 1 or claim 2, wherein each castellation is arranged on an outside circumferential wall of the body.
4. A cutting tool according to any preceding claim, wherein each castellation comprises a leading surface and a trailing surface.
5. A cutting tool according to claim 4, wherein the leading surface of each castellation is taller than the trailing surface.
6. A cutting tool according to claim 4 or claim 5, whcrcin a cutting edge is formed in each castellation between the leading surface and the cutting profile.
7. A cutting tool according to any preceding claim, whcrcin thc first surface of the cutting profile comprises a chamfer that transitions from the radially inner end face of the cutting tool to the radially outer second surface of the cutting profile.
8. A cutting tool according to any preceding claim, wherein the cutting profile comprises a third surface adjacent the second surface.
9. A cutting tool according to claim 8, wherein the third surface transitions between the second surface and an end face of the cutting tool.