WO2023012172A1

WO2023012172A1 - Mould for coating pipeline sections

Info

Publication number: WO2023012172A1
Application number: PCT/EP2022/071728
Authority: WO
Inventors: Michael George; Jason Montgomery
Original assignee: Pipeline Induction Heat Ltd.
Priority date: 2021-08-05
Filing date: 2022-08-02
Publication date: 2023-02-09
Also published as: GB2609905A

Abstract

A mould for coating a section of a pipeline comprises at least first and second mould portions, at least one infill tube having an open end, and at least one valve body. The mould portions are arranged to be fitted together around a pipeline section exterior to enclose the pipeline section and to form an assembled mould cavity between the pipeline section exterior and an interior surface of the mould. The infill tube is fixedly mounted to the first mould portion and is arranged to convey fluid coating material therein and out through its open end and through an infill opening in the interior surface of the mould into the mould cavity. The valve body is arranged to be movable longitudinally within the infill tube to open and close the open end of the infill tube such that, when the end of the infill tube is closed, an end surface of the valve body is substantially flush with the interior surface of the mould.

Description

MOULD FOR COATING PIPELINE SECTIONS

The present invention relates to moulds for coating sections of pipelines, and especially for coating joints between pipe sections of pipelines. The invention has particular utility in the coating of oil or gas pipeline field joints, especially by the injection-moulding of polypropylene or other polymer materials.

Pipelines in the oil and gas industry are typically formed from multiple lengths of steel pipe sections that are welded together end-to-end as they are being laid. To prevent corrosion of the steel pipe sections and to reduce heat loss of fluids transported by the pipelines, the pipe sections are coated with one or more protective and/or insulative layers, typically a multi-layer coating comprising, for example, an epoxy bottom layer (especially fusion-bonded epoxy, FBE) followed by one or more polyethylene (e.g. polypropylene and/or modified polypropylene) outer layer(s). The pipe sections are usually coated at a factory remote from the location in which they are to be laid. This is often referred to as factory-applied coating and it is generally more cost effective than coating pipe sections on site where they are laid. (“On site”, generally known as “in the field”, may be on land, or at sea from a pipe-laying ship.) At the factory, the coating is applied to the outside of the pipe sections and a short length is left uncoated at each end of the pipe section. Each end region of the coating is typically machined to provide a chamfer prior to the field joint coating being applied, and thus the uncoated regions are commonly called “cut-back” regions. The uncoated ends are necessary to enable the steel pipe sections to be welded together to form the pipeline in the field. The welded uncoated ends, known as field joints, must be coated in order to provide the necessary protection and/or insulation, and such coating is known as the field joint coating.

Field joints are commonly coated by means of an injection-moulded polypropylene (“IMPP”) coating process. The IMPP coating process typically commences by blastcleaning the exposed steel pipe section ends and hand-machining (by handheld power tools) the factory coating end portion chamfers to remove oxidation and dirt. The exposed steel pipe section ends are then heated, e.g. by induction heating. A layer of powdered fusion-bonded epoxy primer is then typically applied to the heated pipe section ends, and a thin layer of polypropylene is typically applied to the FBE primer during the FBE curing time. The end regions of the factory-applied coating, including the chamfers, are then heated, e.g. by means of radiant (infrared) heating. The field joint is then completely enclosed in a heavy-duty mould that defines a cavity around the welded pipe joint, the uncoated ends of the pipe sections, and the end regions of the factory-applied coating. Heated molten polypropylene (or modified polypropylene) is then injected into the mould cavity, to fill the cavity, and is allowed to cool. Once the injection-moulded polypropylene has cooled and solidified, the mould is removed from the field joint, leaving the solidified polypropylene field joint coating in place. Extraneous portions of solidified polypropylene due to some mould cavity leakage during the moulding process (mould flashing), and from the polypropylene injection port(s) of the mould, then need to be removed, by hand-machining using handheld power tools.

Other types of field joint coating processes are also known. For example, the injection-moulded polyurethane (IMPII) coating process uses a chemically curable urethane material instead of injecting polypropylene as the mould-infill material around the field joint. Typically, the initial step in the IMPII coating process is to apply a liquid polyurethane primer onto the exposed blast cleaned surface of the welded pipe end sections. Once the primer has been applied, a mould is positioned to enclose the field joint in a cavity and the chemically curable (typically two-component) polyurethane precursor material is injected into the cavity defined by the mould. When the curing process is sufficiently advanced, the mould is removed and the field joint coating is left in place. In each case, extraneous portions of solidified moulded polymer material (mould flashing, etc.) need to be removed by hand-machining.

EP 2590794 discloses known methods and apparatus for coating pipeline field joints, including IMPP methods.

US 10,357,907 discloses a system and method for factory-coating pipe sections of a pipeline, in which extendable and retractable cylindrical supports extend into the mould cavity to support the pipe sections during the moulding process. Each support includes an injector, including an injector valve, for injecting mouldable material into the mould cavity. During the moulding process, once a sufficient quantity of mouldable material has been injected into the mould cavity to support a pipe section, the injection of mouldable material from each support is allowed to drive the supports radially outwardly, thereby simultaneously retracting the supports from the mould cavity and backfilling the spaces created in the mouldable material by the supports. However, this document does not disclose any attempt to minimize or eliminate the amount of mould flashing (extraneous solidified polymer material) created, in the mould-lining openings around each retractable support, and by the retraction of the supports, for example.

There is a need to improve the process of moulding coatings onto pipes and pipelines, e.g. the moulding of field joint coatings, e.g. to reduce or eliminate the amount of mould flashing that is produced and thereby to reduce or eliminate post-moulding handmachining operations.

The present invention seeks to provide improved mould arrangements.

In a first aspect, the present invention provides a mould for coating a section of a pipeline, according to Claim 1 of the appended claims.

Preferred, and other optional, features of the invention are defined and described in the dependent claims.

Accordingly, the invention provides a mould for coating a section of a pipeline, comprising at least first and second mould portions, at least one infill tube having an open end, and at least one valve body, wherein the mould portions are arranged to be fitted together around a pipeline section exterior to enclose the pipeline section and to form an assembled mould cavity between the pipeline section exterior and an interior surface of the mould, wherein the infill tube is fixedly mounted to the first mould portion and is arranged to convey fluid coating material therein and out through its open end and through an infill opening in the interior surface of the mould into the mould cavity, and wherein the valve body is arranged to be movable longitudinally within the infill tube to open and close the open end of the infill tube such that, when the end of the infill tube is closed, an end surface of the valve body is substantially flush with the interior surface of the mould. The pipeline section preferably comprises a joint region, e.g. a field joint, between two pipe sections of a pipeline.

The end surface of the valve body preferably forms part of the interior surface of the mould when the end of the infill tube is closed.

In some preferred embodiments of the invention, at least a portion of the infill tube extends into the infill opening in the interior surface of the mould, such that the open end surface of the infill tube is substantially flush with the interior surface of the mould. In other preferred embodiments of the invention, the infill tube does not extend into the infill opening in the interior surface of the mould.

In preferred embodiments of the invention, the valve body has an elongate shape, preferably a generally cylindrical shape, more preferably a generally right circular cylindrical shape.

A longitudinal axis of the valve body preferably is substantially coaxial with a longitudinal axis of the infill tube.

Preferably, the valve body includes a sealing surface configured to contact a corresponding sealing surface of the infill tube, preferably in the interior of the infill tube, to close the end of the infill tube. Preferably the sealing surface of the valve body is configured to be spaced apart from the corresponding sealing surface of the infill tube, preferably in the interior of the infill tube, to open the end of the infill tube. The valve body and the infill tube, and more particularly the sealing surfaces of the valve body and the infill tube, preferably therefore form an infill valve which may be opened to inject fluid coating material into the mould cavity, and closed to stop or prevent fluid coating material being injected into the mould cavity.

The sealing surface of the valve body preferably is a circumferential sealing surface, around an external circumference of the valve body. Preferably, the sealing surface of the valve body is set back from the end surface of the valve body. The corresponding sealing surface of the infill tube preferably is a circumferential sealing surface, preferably around an interior circumference of the infill tube. Preferably, the corresponding sealing surface of the infill tube is set back from the open end of the infill tube.

The sealing surface of the valve body preferably comprises a shoulder surface, preferably a generally frusto-conical shoulder surface. Additionally or alternatively, the corresponding sealing surface of the infill tube preferably comprises a shoulder surface, preferably a generally frusto-conical surface, preferably in the interior of the infill tube.

When the sealing surface of the valve body is spaced apart from the corresponding sealing surface in the interior of the infill tube, the sealing surface of the valve body preferably is longitudinally set back from the corresponding sealing surface in the interior of the infill tube.

In preferred embodiments of the invention, there is a gap, preferably a circumferential gap, between at least part of a length of the valve body and at least part of a length of the infill tube. The gap preferably is open to the open end of the infill tube when the sealing surface of the valve body is spaced apart from the corresponding sealing surface of the infill tube. The gap preferably is arranged to convey fluid coating material into the mould cavity when the end of the infill tube is open.

Preferably, the valve body is configured to be movable longitudinally within the infill tube to open and close the open end of the infill tube, by means of at least one actuator. The actuator preferably comprises a hydraulic and/or pneumatic actuator, e.g. comprising a hydraulic and/or a pneumatic cylinder and piston.

A controller of the mould may be configured to control the actuator(s) and/or other components and/or systems and/or processes of the mould and the moulding process.

In some preferred embodiments of the invention, the mould comprises a plurality of infill tubes, each infill tube including a valve body therein. Preferably, the plurality of infill tubes are configured to be connected to a single supply of fluid coating material. The interior surface of the assembled mould preferably substantially comprises a right circular cylinder, preferably an elongate right circular cylinder. For example, the mouldinterior surface of each of the first and second mould portions preferably comprises a longitudinal section of the cylinder. When the mould is assembled around a pipeline section in use, there are preferably joins, more preferably sealed joins, between the first and second mould portions. The joins preferably are elongate and substantially parallel to the longitudinal axis of the cylinder. The end surface of the valve body preferably is cylindrically concave and is configured to form part of the longitudinal section of the cylinder formed by the first mould portion.

In preferred embodiments of the invention, the infill tube and the valve body are formed from metal, preferably steel, more preferably stainless steel.

In preferred embodiments of the invention, the mould-interior surface of each of the first and second mould portions is formed by a mould lining layer. The mould lining layer preferably is formed from steel, preferably stainless steel. The remainder of the mould may be formed from steel.

In preferred embodiments, the mould further comprises at least one external support frame arranged to support the mould portions. The external support frame preferably is configured to enable relative movement between the first and second mould portions, more preferably comprising relative pivoting movement, to cause the first and second mould portions to be fitted together around a pipeline section exterior, in use, and preferably also to cause the mould portions to be separated from each other once the moulding process has finished. Advantageously, the external support frame may include one or more actuators, preferably hydraulic actuators, arranged to cause the relative movement between the first and second mould portions, in use. A controller may be configured to control the actuators and/or other components and/or systems and/or processes of the mould and the moulding process. In at least some preferred embodiments of the invention, the mould further comprises at least a third mould portion. Preferably, there is the same number of joins and mould portions in the mould according to the invention. That is, when there are two mould portions preferably there are two joins between the mould portions in use, and when there are three mould portions preferably there are three joins between the mould portions in use, for example.

A preferred embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, of which:

Figure 1 (a) and (b) show cross-sectional and plan views, respectively, of a mould portion of part of a known mould for coating a section of a pipeline;

Figure 2(a) and (b) show cross-sectional and plan views, respectively, of an embodiment of a first mould portion of a mould according to the invention, with infill tubes open;

Figures 3 shows a detail D of Figure 2(a);

Figure 4(a) and (b) show cross-sectional and plan views, respectively, of the first mould portion of the mould shown in Figure 2(a) and (b), with infill tubes closed;

Figure 5 shows a detail B of Figure 4(a);

Figure 6 shows a cross-sectional view of the entire mould of Figure 2, in an open configuration; and

Figures 7 shows a perspective view of the entire mould of Figure 2, in another open configuration.

Figure 1 (a) and (b) show cross-sectional and plan views, respectively, of a semi- cylindrical mould portion 3 of a known mould 1 for coating a section of a pipeline (not shown in Figure 1 , but shown schematically in Figure 6), e.g. a pipeline field joint. The known mould portion 3 has an infill tube 5 fixedly mounted thereto, for injecting fluid coating material (e.g. polypropylene and/or other polymer material) into the mould cavity 7 of the mould 1. The infill tube 5 has a valve 9 therein, in the form of a steel plate assembly for opening and closing the infill tube 5, to inject, or to prevent the injection of, (respectively), fluid coating material into the mould cavity 7. The known valve 9 is closed or opened (respectively) by moving a steel plate across the interior of the infill tube 5 so as to block it, or out of the interior of the infill tube 5 so as to free it. As can be seen in Figure 1(a), there is a significant length 11 of the infill tube 5 situated between the valve 9 and the interior surface 13 of the mould 1. In use, when the coating material fills the mould cavity 7 and solidifies, solidified coating material remains in the length 11 of the infill tube 5. Such extraneous solidified coating material forms mould flashing I sprue material which subsequently needs to be removed both from the coated pipeline and from the infill tube 5.

Figures 2 to 7 show various complete and partial views of an embodiment of a mould 15 for coating a section 17 of a pipeline. The pipeline section 17 (indicated schematically in Figure 6) preferably comprises a field joint between two pipe sections of a pipeline. The illustrated mould 15 comprises a first mould portion 19, a second mould portion 21 , and a third mould portion 23, but the mould according to the invention can instead comprise two, or more than three, mould portions. The mould portions 19, 21 and 23 are arranged to be fitted together around an exterior 25 of a pipeline section 17 to enclose the pipeline section 17 and to form an assembled mould cavity 27 (part of which is shown in Figure 6) between the pipeline section exterior 25 and an interior surface 29 of the mould 15.

The first mould portion 19 generally comprises a substantially semi-cylindrical longitudinal section of a right circular cylinder, and is arranged to be positioned adjacent to an underside of a pipeline field joint 17. Each of the second 21 and third 23 mould portions comprises a substantially quarter-cylindrical longitudinal section of a right circular cylinder, and is arranged to be positioned adjacent to an upper side of the pipeline field joint 17, to complete the generally cylindrical shape of the assembled mould portions. The interior surface 29 of the assembled mould 15 substantially comprises an elongate right circular cylinder, and the mould-interior surface 29 of each of the first, second and third mould portions 19, 21 and 23 comprises a longitudinal section of the cylinder. The mould-interior surface 29 of each of the mould portions 19, 21 , 23 is formed by a mould lining layer 31 which preferably is formed from steel, more preferably stainless steel. The remainder of the mould 15 may be formed from steel.

When the mould 15 is assembled around a pipeline section 17 in use, there are joins 33 between the mould portions, the joins 33 being elongate and substantially parallel to the longitudinal axis of the cylinder. In the illustrated embodiment, the first mould portion 19 includes two seal members 35 protruding therefrom along opposite edges of the first mould portion 19, to seal the joins 33 between the first 19 and second 21 mould portions, and between the first 19 and third 23 mould portions, respectively. The second mould portion 21 also includes a longitudinal seal member 35 for sealing the join 33 between the second 21 and third 23 mould portions. The third mould portion 23 does not include any longitudinal seal members, because the joins it forms with the first 19 and second 21 mould portions are sealed by the seal members carried by those mould portions. It is apparent that there is the same number of joins 33, seal members 35 and mould portions, in the mould 15, i.e. three of each, in the illustrated embodiment.

As shown in figures 6 and 7, the illustrated complete mould 15 includes external support frame 37 arranged to support the mould portions 19, 21 , 23. The external support frame 37 is configured to enable pivoting movement of the second 21 and third 23 mould portions relative to the first mould portion 19, to cause the mould portions to be fitted together around the pipeline section exterior 25, and also to cause the mould portions 19, 21 , 23 to be separated from each other once the moulding process has finished. For this purpose, the external support frame 37 includes a plurality of hydraulic actuators 39 which are arranged to cause the pivoting movement of the second 21 and third 23 mould portions, in use. A controller (not shown) may be configured to control the hydraulic actuators 39 and/or other components and/or systems and/or processes of the mould 15 and the moulding process.

The longitudinal ends of the mould cavity 27 are defined by circumferential metal (preferably steel) seals 41 , for sealing between the interior surface 29 of the mould 15 and the exterior surface 25 of the pipeline sections 17. In use, fluid coating material, e.g. molten polymer material (for example polypropylene) is injected into the mould cavity 27 via a pair of infill tubes 43 (a single infill tube 43, or a larger number of infill tubes, could instead be employed). As illustrated, the plurality of infill tubes 43 are connected to a single supply 44 of fluid coating material.

Figure 2(a) and (b) show cross-sectional and plan views, respectively, of the first mould portion 19 of the mould 15, with the ends 45 of the two infill tubes 43 open for the injection of fluid coating material into the mould cavity 27. Figure 3 shows a detail D of Figure 2(a). Figure 4(a) and (b) show cross-sectional and plan views, respectively, of the first mould portion 19 of the mould 15, with the ends 45 of the two infill tubes 43 closed to stop or prevent the injection of fluid coating material into the mould cavity 27. Figure 5 shows a detail B of Figure 4(a).

Each infill tube 43 is fixedly mounted to the first mould portion 19, e.g. via the external support frame 37 (for example by means of one or more fasteners and/or by welding to the support frame 37), and is arranged to convey fluid coating material therein and out through an open end 45 thereof, and through an infill opening 47 in the interior surface 31 of the mould 15, into the mould cavity 27. As illustrated, a portion of each infill tube 43 extends into the corresponding infill opening 43 in the interior surface 29 of the mould 15 (in the mould cavity lining layer 31), such that the open end surface 46 of the infill tube 43 is substantially flush with, and forms part of, the interior surface 29 of the mould 15. The end 45 of the infill tube 43 is a close fit in the infill opening 47 (and/or may be welded) such that there is substantially no gap between the end 45 of the infill tube and the interior surface 29 of the first mould portion 19. (Alternatively, in other embodiments of the invention, the infill tube 43 does not extend into the infill opening 47 in the interior surface 29 of the mould 15, and instead the open end surface 46 of the infill tube 43 buts-up against the external surface of the mould cavity lining layer 31. In such embodiments, the infill opening 47 has a smaller diameter, sized to be substantially the same diameter as that of the open end 45 of the infill tube, and coaxial therewith.)

Each infill tube 43 includes a valve body 49 that is arranged to be movable longitudinally within the infill tube 43 to open and close the open end 45 of the infill tube. Each valve body 49 is longitudinally movable within its respective infill tube 43 such that, when the open end 45 of the infill tube 43 is closed, an end surface 51 of the valve body 49 is substantially flush with the interior surface 29 of the mould 15. The end surface 51 of each valve body 49 thereby forms part of the interior surface 29 of the mould 15 when the end 45 of the infill tube 43 is closed. In the illustrated embodiment, the end surface 51 of each valve body 49 is advantageously cylindrically concave and configured to conform to the substantially cylindrical shape of the mould-interior surface 29 of the mould 15.

As illustrated, each valve body 49 has an elongate shape, more particularly a generally cylindrical shape, especially a generally right circular cylindrical shape, and a longitudinal axis of each valve body 49 is substantially coaxial with a longitudinal axis of its respective infill tube 43. Each valve body 49 includes a sealing surface 53 configured to contact a corresponding sealing surface 55 of the infill tube 43, in the interior of the infill tube 43, in order to close the end 45 of the infill tube 43. The sealing surface 53 of each valve body 49 is configured to be spaced apart (longitudinally set back) from the corresponding sealing surface 55 of the infill tube 43, in the interior of the infill tube 43, in order to open the end of the infill tube 43. The valve body 49 and the infill tube 43, and more particularly the respective sealing surfaces 53 and 55 of the valve body 49 and the infill tube 43, therefore form an infill valve which may be opened to inject fluid coating material into the mould cavity 27, and closed to stop or prevent fluid coating material being injected into the mould cavity 27. Each infill tube 43 and valve body 49 is advantageously formed from steel, preferably stainless steel.

The sealing surface 53 of each valve body 49 is a circumferential sealing surface, around an external circumference of the valve body 49, and is set back from the end surface 51 of the valve body 49. The corresponding sealing surface 55 of the infill tube 43 is also a circumferential sealing surface, around an interior circumference of the infill tube 43, and is set back from the open end 45 of the infill tube 43. As shown, the sealing surface 53 of each valve body 49 has the form of a shoulder surface, in particular a generally frusto- conical shoulder surface. The corresponding sealing surface 55 of each infill tube 43 also comprises a shoulder surface (facing in the opposing direction to that of the valve body 49), in particular a generally frusto-conical should surface, in the interior of the infill tube 43. There is a circumferential gap 57 between part of a length of each valve body 49 and part of a length of the infill tube 43 in which it is situated. The circumferential gap 57 is open to the open end 45 of the infill tube 43 when the sealing surface 53 of the valve body 49 is spaced apart from the corresponding sealing surface 55 of the infill tube 43. The circumferential gap 57 is arranged to convey fluid coating material into the mould cavity 27 when the end 45 of the infill tube 43 is open. Each valve body 49 is configured to be movable longitudinally within its respective infill tube 43 to open and close the open end 45 of the infill tube 43, by means of an actuator 59. Advantageously, each actuator 59 comprises a hydraulic and/or pneumatic actuator, comprising a hydraulic and/or a pneumatic cylinder 61 and piston 63. A controller (not shown) may be configured to control the actuators 59, e.g. via hydraulic and/or a pneumatic lines 65. The controller may also be configured to control other components and/or systems and/or processes of the mould 15 and the moulding process.

Each infill tube 43 is connected to the supply 44 of fluid coating material, for the conveyance of the fluid coating material, via a respective supply tube 48. In the illustrated embodiment, the longitudinal axis of each supply tube 48 is substantially perpendicular to the longitudinal axis of the infill tube 43 to which it is connected, but other angles and arrangements are possible. As illustrated in figures 2(a) and 4(a), a fluid connection between the circumferential gap 57 and the supply tube 48, at the junction 50 between each supply tube 48 and its respective infill tube 43, may be open or closed depending upon the position of the valve body 49. Figures 2(a) and 3 show the valve bodies 49 in their longitudinally backward position, thereby providing an open fluid connection from the supply 44 of fluid coating material, through the supply tubes 48, into the infill tubes 43, through the circumferential gaps 57, and out through the open ends 45 of the infill tubes and infill openings 47 and into the mould cavity 27. Figures 4(a) and 5 show the valve bodies 49 in their longitudinally forward position, such that a larger diameter part 52 of each valve body 49, situated longitudinally backward of the gap 57, substantially closes the junction 50 between each supply tube 48 and its respective infill tube 43, thereby, in concert with the above-described closing of the open end 45 of each infill tube 43, closing such fluid connection and stopping or preventing the infill of fluid coating material into the mould cavity 27.

It will be understood that the above description and the drawings are of a particular example embodiment of the invention, but that other implementations and embodiments of the invention are included in the scope of the claims.

Claims

1. A mould for coating a section of a pipeline, comprising at least first and second mould portions, at least one infill tube having an open end, and at least one valve body, wherein the mould portions are arranged to be fitted together around a pipeline section exterior to enclose the pipeline section and to form an assembled mould cavity between the pipeline section exterior and an interior surface of the mould, wherein the infill tube is fixedly mounted to the first mould portion and is arranged to convey fluid coating material therein and out through its open end and through an infill opening in the interior surface of the mould into the mould cavity, and wherein the valve body is arranged to be movable longitudinally within the infill tube to open and close the open end of the infill tube such that, when the end of the infill tube is closed, an end surface of the valve body is substantially flush with the interior surface of the mould.

2. A mould according to Claim 1 , wherein the end surface of the valve body forms part of the interior surface of the mould when the end of the infill tube is closed.

3. A mould according to Claim 1 or Claim 2, wherein at least a portion of the infill tube extends into the infill opening in the interior surface of the mould, such that the open end surface of the infill tube is substantially flush with the interior surface of the mould.

4. A mould according to Claim 1 or Claim 2, wherein the infill tube does not extend into the infill opening in the interior surface of the mould.

5. A mould according to any preceding claim, wherein the valve body has an elongate shape, preferably an elongate generally right circular cylindrical shape.

6. A mould according to any preceding claim, wherein the valve body includes a sealing surface configured to contact a corresponding sealing surface of the infill tube to close the end of the infill tube, and wherein the sealing surface of the valve body is configured to be spaced apart from the corresponding sealing surface of the infill tube to open the end of the infill tube. A mould according to Claim 6, wherein the sealing surfaces of the valve body and the infill tube form an infill valve which may be opened to inject fluid coating material into the mould cavity, and closed to stop or prevent fluid coating material being injected into the mould cavity. A mould according to Claim 6 or Claim 7, wherein the corresponding sealing surface of the infill tube is in the interior of the infill tube. A mould according to any one of claims 6 to 8, wherein the sealing surface of the valve body is a circumferential sealing surface, around an external circumference of the valve body. A mould according to any one of claims 6 to 9, wherein the sealing surface of the valve body is set back from the end surface of the valve body. A mould according to any one of claims 6 to 10, wherein the corresponding sealing surface of the infill tube is a circumferential sealing surface, preferably around an interior circumference of the infill tube. A mould according to any one of claims 6 to 11 , wherein the corresponding sealing surface of the infill tube is set back from the open end of the infill tube, preferably in the interior of the infill tube. A mould according to any one of claims 6 to 12, wherein the sealing surface of the valve body comprises a shoulder surface, preferably a generally frusto-conical shoulder surface. A mould according to any one of claims 6 to 13, wherein the corresponding sealing surface of the infill tube comprises a generally frusto-conical surface, preferably in the interior of the infill tube.

15. A mould according to any one of claims 6 to 14, wherein when the sealing surface of the valve body is spaced apart from the corresponding sealing surface in the interior of the infill tube, the sealing surface of the valve body is longitudinally set back from the corresponding sealing surface in the interior of the infill tube.

16. A mould according to any one of claims 6 to 15, wherein there is a gap, preferably a circumferential gap, between at least part of a length of the valve body and at least part of a length of the infill tube, and wherein the gap is open to the open end of the infill tube when the sealing surface of the valve body is spaced apart from the corresponding sealing surface of the infill tube.

17. A mould according to Claim 16, wherein the gap is arranged to convey fluid coating material into the mould cavity when the end of the infill tube is open.

18. A mould according to any preceding claim, wherein the valve body is configured to be movable longitudinally within the infill tube to open and close the open end of the infill tube, by means of at least one actuator.

19. A mould according to Claim 18, wherein the actuator comprises a hydraulic and/or pneumatic actuator.

20. A mould according to any preceding claim, comprising a plurality of said infill tubes, each infill tube including a said valve body therein.

21. A mould according to Claim 20, wherein the plurality of infill tubes are configured to be connected to a single supply of fluid coating material.

22. A mould according to any preceding claim, wherein the interior surface of the assembled mould substantially comprises a right circular cylinder, preferably an elongate right circular cylinder.

15 A mould according to Claim 22, wherein the mould-interior surface of each of the first and second mould portions comprises a longitudinal section of the cylinder. A mould according to Claim 23, wherein the end surface of the valve body is cylindrically concave and is configured to form part of the longitudinal section of the cylinder formed by the first mould portion. A mould according to any preceding claim, wherein the pipeline section comprises a joint region between two pipe sections of the pipeline.

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