SECTION OF COATED PIPE AND METHOD FOR COATING A PIPE.

MX431828BActive Publication Date: 2026-02-252543500 ALBERTA LTD D B A SHAW PIPE PROTECTION
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Patent Information

Application Number
MX2022000010
Authority / Receiving Office
MX · MX
Patent Type
Patents
Current Assignee / Owner
Priority Date
2019-06-25
Filing Date
2022-01-03
Publication Date
2026-02-25
Estimated Expiration
2040-06-25

AI Technical Summary

Technical Problem

Existing methods for manufacturing pipes with embedded hollow channels in coating layers are costly, time-consuming, and compromise the long-term integrity of the pipe coating, particularly for underwater applications requiring insulation that can withstand seawater and hydrostatic pressures.

Method used

A method involving a coating system that embeds elongated members within circumferential liner layers, allowing for the formation of channels without grooving the casing, and applying multiple layers including anti-corrosion and insulating layers, with optional topcoats, to create a multi-layer coated steel tube that can resist hydrostatic pressures.

Benefits of technology

The method enables efficient and cost-effective production of pipes with embedded channels that maintain pipe integrity, allowing for heat transfer and sensor integration, suitable for underwater use.

✦ Generated by Eureka AI based on patent content.

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Abstract

A method for manufacturing sheathed tube sections containing a hollow conduit or electrical cable within the sheath is described. The tube sections themselves are also described. The hollow conduit can be used to house sensors, optical fiber, or heating wire within the sheath.
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Description

LINED PIPE SECTION AND METHOD FOR LINED A PIPE FIELD OF INVENTION The present description relates to a coated pipe section and a method for coating a pipe section, particularly for manufacturing a pipe section with one or more coating layers. BACKGROUND OF THE INVENTION An oil or gas pipeline is typically made from a plurality of steel pipe sections joined end-to-end through what is frequently referred to as a “circumferential weld” - a weld around the perimeter of the steel pipe sections. In addition, a pipe is typically coated for impact and corrosion resistance, as well as for insulation and / or weight reduction. Multiple coatings are possible. For example, a metal pipe might be coated with a thin layer of epoxy, followed by a layer of polyolefin (such as polyethylene or polypropylene). This could then be followed by a layer of insulating foam and a top coating layer of polyethylene, for example, or a layer of concrete. Often, the polyolefin coating is quite thick. It would be desirable to incorporate additional functionality into the thick coating. For example, it might be desirable to embed sensors, such as fiber optic cables, within the coating layer to detect various operating conditions, such as a potential leak, in the pipe.Alternatively, it may be desirable to introduce heating cables into the thermal insulation layer to improve the thermal insulation of the pipe to maintain the flow of hydrocarbon transported in it. Pipe linings incorporating channels are known in the prior art. However, methods for ensuring this still leave much to be desired. For example, known methods for manufacturing channels within pipe linings, as described in U.S. Patent 6,328,074, incorporated herein by reference, typically involve first forming lining layers with at least one machined or formed groove. After placing the heating wire or fiber optic cables in the grooves, they are filled using another lining process. The multiple discrete manufacturing steps in the above method are costly and time-consuming and can compromise the long-term integrity of the pipe lining. Other examples of methods for applying a conduit to a tube can be found in U.S. Patent 6,528,004, U.S. Patent 6,940,054, U.S. Patent Publications 20070034274, 20080006337 and 20150053293, as well as PCT Publication WO 2020 / 058769A1, all incorporated herein by reference. There is a need for an improved manufacturing method for pipes with hollow channels embedded within the lining layers, and for the equipment to achieve this. There is a particular need for methods for use with pipes lined with moist thermal insulation, for underwater use, where the insulation must withstand direct contact with seawater and underwater hydrostatic pressures. There is also a need for an improved pipe that has an insulating coating layer capable of making direct contact with seawater and underwater hydrostatic pressures, and that has hollow channels embedded within the coating, where the channels are formed to maximize heat transfer to the underlying pipe. BRIEF DESCRIPTION OF THE INVENTION According to one aspect of the present invention, a method for coating a tube section is provided, the method comprising: displacing the tube section longitudinally through a coating system; displacing at least one elongated member through the coating system concurrently with the tube section; applying a circumferential coating layer by means of the coating system to the tube section, wherein at least one elongated member is embedded within the circumferential coating layer. According to certain modalities, where the coating layer is an anti-corrosion layer, a polyolefin layer or an insulating layer. According to certain variations, the method also includes applying at least one additional layer before the overlay of the coating layer. In certain embodiments, the coating layer is a polyolefin layer and at least one additional layer comprises an anti-corrosion layer applied before the coating layer. In certain embodiments, the coating layer is a polyolefin layer and at least one additional layer comprises an insulating layer applied over the coating layer. In certain embodiments, the coating layer is an insulating layer and at least one additional layer comprises an anti-corrosion layer applied before the coating layer. In certain embodiments, the coating layer is an insulating layer and at least one additional layer comprises a polyolefin layer applied before the coating layer. In certain forms, the method also includes applying a top coating layer on top of the coating layer or insulating layer. In certain configurations, the anti-corrosion layer applied before the coating layer is of variable thickness, having a thinner coating in areas where at least one elongated member is to be placed and a thicker coating in areas where no elongated member is to be placed. In certain models, the anti-corrosion layer is applied before the coating layer, which is thermally conductive and electrically insulating. In certain forms, the elongated member is a solid rod. In certain forms, the method also includes removing at least one elongated member from the lining layer to form at least one channel in it. In certain modalities, removal involves applying a force to displace the elongated member from the lining layer. In certain forms, the elongated member has a continuous cross-section and at least one internal channel. In certain forms, the elongated member is a tubular rod with an internal channel. In certain embodiments, an additional elongated member with a continuous cross-section is also embedded between the elongated member and the underlying tube or layer. In certain forms, the additional elongated member is made of a material that is the same or similar to that of the elongated member. In certain models, the additional elongated member is made of a material with high thermal conductivity. In certain forms, the elongated member has a continuous cross-section with at least one internal channel. In certain embodiments, the elongated member has a cross-sectional shape which increases the contact surface area between the elongated member and the underlying tube or layer. In certain configurations, the elongated member is made of a material that is the same or similar to that of the coating layer. In certain forms, the elongated member is made of a polymer composition with preferably increased thermal conductivity. In certain models, the elongated member is made of a reinforced polymer composition for improved mechanical strength. In certain forms, the elongated member is made of a polymer composition with preferably increased thermal conductivity and reinforced for improved mechanical strength. In certain embodiments, at least one internal channel of the elongated member is filled with pressurized gas when the elongated member is embedded in the lining layer. In certain models, the pressurized gas is circulated continuously. In certain models, the pressurized gas is cooled. In certain versions, the elongated member is metallic. In certain forms, the elongated member is an electrically conductive cable. In certain modalities, the coating system is or comprises a cross die. In certain models, the cross die is formed to allow the passage of the elongated member. In certain configurations, the coating system is or comprises a side extruder. In certain configurations, the displacement of the tube section through the lining system also includes rotating the tube section. In certain modalities, the method also involves placing at least one of the heating cables, fiber optic cables, or sensors inside the channel. In certain configurations, the channel is parallel to the tube section. In certain models, the channel is helical around the tube section. According to a further aspect of the present invention, a multi-layered coated steel tube is provided, comprising: an inner steel tube; an outer layer of thermal insulation; at least one elongated member embedded within the thermal insulation, with a continuous cross-section and optionally at least one internal channel. According to certain modalities, the continuous cross-section is formed to increase the surface contact area with the inner steel tube. In certain models, the outer layer of thermal insulation is capable of withstanding more than 1 MPa of hydrostatic pressure. In certain models, the outer layer of thermal insulation is capable of withstanding more than 5 MPa of hydrostatic pressure. In certain models, the outer layer of thermal insulation is capable of withstanding more than 10 MPa of hydrostatic pressure. In certain models, the outer layer of thermal insulation is capable of withstanding more than 30 MPa of hydrostatic pressure. In certain embodiments, the multi-layered coated steel tube also comprises at least one additional layer below or above the thermal insulation layer. In certain versions, at least one additional layer comprises an anti-corrosion layer under the thermal insulation layer. In certain configurations, at least one additional layer also comprises one or more layers of additional thermal insulation. In certain forms, the multi-layered coated steel tube also comprises an outer top coating layer. In certain configurations, the anti-corrosion layer is preferably thinned in the areas between the elongated member and the inner steel tube. In certain forms, the anti-corrosion layer consists or partially consists of a material which is preferably thermally conductive and electrically insulating. In certain forms, the elongated member is made of a material that is the same or similar to the thermal insulation. In certain forms, the elongated member is made of a polymer composition with preferably increased thermal conductivity. In certain models, the elongated member is made of a reinforced polymer composition for improved mechanical strength. In certain versions, the elongated member is metallic. In certain forms, the elongated member is an electrically conductive cable. According to a further aspect of the present invention, a multi-layered coated steel tube is provided, comprising: an inner steel tube; an outer layer of thermal insulation; at least one elongated member embedded within the thermal insulation, having a continuous cross-section and optionally at least one internal channel; an additional elongated member with a continuous cross-section located between each of at least one of the elongated members and the inner steel tube. In certain configurations, the outer layer of thermal insulation is capable of withstanding hydrostatic pressure of at least 1 MPa, for example, more than 5 MPa, more than 10 MPa or more than 30 MPa. According to certain modalities, the multi-layered coated steel tube further comprises at least one additional layer below or above the thermal insulation layer. According to certain modalities, at least one additional layer comprises an anti-corrosion layer under the thermal insulation layer. According to certain modalities, at least one additional layer also comprises one or more additional layers of thermal insulation. According to additional modalities, the multi-layered coated steel tube further comprises an outer top coating layer. According to certain modalities, the anti-corrosion layer is preferably thinned in the areas between the elongated member and the inner steel tube. According to certain modalities, the anti-corrosion layer consists or consists partially of a material which is preferably thermally conductive and electrically insulating. According to certain modalities, at least one elongated member is made of a material that is the same or similar to the thermal insulation. According to certain modalities, at least one elongated member of polymeric composition with preferably increased thermal conductivity. According to certain modalities, at least one elongated member of reinforced polymer composition for improved mechanical strength. According to certain modalities, at least one elongated member is made of a polymer composition with preferably increased thermal conductivity and reinforced for improved mechanical strength. According to certain models, at least one elongated member is metallic. According to certain modalities, at least one elongated member is an electrically conductive cable. According to certain modalities, the additional elongated member is made of the same or similar material as at least one elongated member. According to certain modalities, the additional elongated member has a higher thermal conductivity than at least one elongated member. According to one aspect of the present invention, a method for coating a tube section is provided, the method comprising: displacing the tube section longitudinally through a coating system; displacing at least one elongated member through the coating system concurrently with the tube section; applying a plurality of circumferential coating layers by means of the coating system to the tube section, wherein at least one elongated member is fully or partially embedded within one of the plurality of circumferential coating layers. BRIEF DESCRIPTION OF THE FIGURES Reference will now be made, by way of example, to the accompanying Figures which show exemplary forms of the present application and in which: Figure 1 is a schematic view of a pipe section displaced through a lining system according to an exemplary method of the present description; Figure 2 is a cross-sectional view of the casing tube section along the AA direction in Figure 1; The second end 20 of the tube section 12 is moved through the ring 24 of the lining system 14 concurrently with the tube section 12. As can be appreciated by those skilled in the prior art, the number of elongated members 28 can be varied as required. The elongated members can be placed circumferentially around the tube section 12, either separately and uniformly, or clustered within one or more areas as required. Although the elongated members 28 are shown straight and positioned parallel to the tube section 12, it should be appreciated that the elongated members 28 can be of any suitable shape. For example, in some embodiments, the elongated member 28 can be helical so that it can be spirally placed around the tube section 12. The elongated member 28 can also be sinusoidal, zigzag, or another shape as required. In addition to having a circular cross-section as shown, the elongated members 28 can be of any suitable cross-sectional shape, including but not limited to rectangular, square, oval, triangular, or irregular shapes, for example, a "saddle" shape that "hangs" from the circumference of the pipe or casing. The cross-sectional area of ​​the elongated member 28 defines the dimensions of the channel that will be formed in the casing layers. During the extrusion of the coating material into ring 24 of the coating system 14, one or more elongated members 28 are coated with the coating material to become embedded within the coating 30 formed therefrom. It should be appreciated that the coating system 14 may be a multi-layer coating system that applies a plurality of coating layers to the pipe section 12, and consequently, the coating 30 may comprise a plurality of coating layers. As shown in the exemplary embodiment in Figure 2, the plurality of layers may include an anti-corrosion layer 29 immediately covering the steel pipe 12 to provide waterproof protection, for example, a fusion-bonded epoxy layer. The anti-corrosion layer 29 may be covered with a polyolefin layer (not shown), an insulating layer 32, and / or an outer protective layer (top coating) 34. Although the elongated members 28 are shown as embedded within the thermal insulating layer 32 in Figure 2, it should be appreciated that the elongated members 28 can be embedded within any or multiple layers of the plurality of cladding layers. The position of the elongated members 28 within the layer in which they are embedded can be varied as needed by adjusting the lining system configurations, as described in more detail below. In the configuration shown in Figure 2, the elongated members 28, and the channels formed by them, are positioned very close to the pipe section 12. This configuration may be preferred for heating purposes since the channels created by the elongated members are closer to the pipe section 12. This allows for better heat diffusion and therefore more effective heating of the pipe section 12, preventing the hydrocarbon material carried within the pipes from solidifying at low temperatures. Figure 3 shows a close-up cross-sectional view of Figure 2, illustrating that the elongated members 28 are spliced ​​into the anti-corrosion lining 29.In Figure 3, the elongated member 28 is shown located within the insulating layer 32, splicing the anti-corrosion layer 29. Figure 4 shows an alternative configuration, where the elongated member 28 is configured to be inside the anti-corrosion layer 29. This can be done by making the anti-corrosion layer 29 thinner at circumferential locations where an elongated member 28 is to be placed, or alternatively, by placing the elongated member 28 on the pipe while the anti-corrosion layer 29 is still soft and has not yet cured. In some embodiments, the thickness of the thermal insulation layer can be reduced to accommodate the embedding of heating elements within it. Consequently, the overall thickness of the cladding layers is reduced. Furthermore, in certain embodiments, the anti-corrosion layer, which can be thermally conductive and / or electrically insulating, can be applied at varying thicknesses, depending on whether an elongated member 28 is placed on top of it. For example, the anti-corrosion layer can be applied thinner in areas where the elongated members will be located and thicker in areas where they will not. This can aid, for example, in heat transfer from the channels to the steel tube. To aid heat transfer, a saddle configuration can be used, as shown in Figures 5 and 6. The saddle 37 can be made of the same material as the elongated member 28 or it can be a highly heat-conducting material, such as aluminum. The saddle 37 can be integrated with the elongated member as a separate piece. In some embodiments, the elongated members 28 can be made of solid metal rods. After cooling the cladding material on the tube section 12, the metal rods can be removed from the cladding layers by applying sufficient force from one end. Removal of the metal rods results in a corresponding number of channels 36 within the cladding layers. The channels 36 can be configured to receive heating elements, fiber optic sensors, or any other suitable equipment. The rod can preferably be made of smooth metal with a low coefficient of friction with the cladding material, or coated to create a low coefficient of friction with the cladding material, thus facilitating easier removal. It should be noted that any other method of removing the elongated member 28 from the cladding material may be used. In some configurations where the heating elements are inserted into channel 36, the temperature of the heating elements must be set below the softening point of the material from which the thermal insulation layer 36 is made. For example, for synthetic foam, the temperature should not exceed 80 degrees Celsius, with a preferred average temperature of 60 degrees Celsius. For polypropylene foam, the maximum temperature should not exceed 120 degrees Celsius, with a preferred average temperature of approximately 90 degrees Celsius. For solid polypropylene or styrene material, the maximum permissible temperature is approximately 150 and 95 degrees Celsius, respectively.In some configurations, the foam material used in one or more of the lining layers can be specifically designed taking into consideration the interactions between the heating elements and the lining system. In some forms, the elongated limbs 28 can be made of an electrically conductive wire. In some embodiments, the elongated members 28 can be made of hollow rods (like a tubular rod), each with an internal channel. In some embodiments, the hollow rods can be used in a manner similar to solid rods, as discussed previously. In some other embodiments, after the casing layers are formed, the hollow rods are not removed and are left within one or more of the casing layers. The internal channel can be circular or have a different cross-sectional shape, which increases the contact surface area between the elongated member and the underlying tube or layer. The internal channel can be circular, and the external cross-section can have a different cross-sectional shape, which increases the contact surface area between the elongated member and the underlying tube or layer.For example, the bottom of the cross-section of the elongated member can be shaped to generally conform to a portion of the circumference of the tube to be placed next to it in a shape referred to as a "saddle". In some configurations, multiple rods can be used, one above the other (for example) or at different relative depths within the cladding layer. This can be useful, for example, where elongated members create channels and the channels are used for different purposes—for example, to heat cable closer to the steel of the conduit and fiber optic cable farther from the steel of the conduit. In some preferred embodiments, the tubular rods can be made of the same material as the coating layer in which they are to be embedded. This ensures a strong bond between the coating layer and the tubular rods. The surface of the tubular rods can be preheated by appropriate means before insertion into the coating layer to facilitate bonding. In some designs, the elongated member can be made of a polymer composition with higher thermal conductivity than the coating layer in which it is embedded. The polymer composition can be reinforced for improved mechanical strength. In cases where the elongated member has an internal channel, and where the elongated member is made of a material similar to that of the layer into which it will be embedded, filling the internal channel of the elongated member with pressurized gas while the elongated member is being embedded has been found to improve performance and reduce the likelihood of internal channel collapse during installation. The pressurized gas can be continuously circulated in the internal channel and can be cooled to further enhance the integrity of the elongated member during the coating process. When the tube section 12 and the elongated member 28 are moved through the lining system 14, the tube section and the elongated member 28 can be kept without rotation. Alternatively, at least one of the tube section 12 and the elongated member 28 can be rotated while being moved through the lining system 14. As can be seen from the above, this description outlines methods for coating a section of pipe where only one pass through the coating system may be required, although in certain configurations, multiple passes can be used to build up a full-thickness coating. Furthermore, the coating layers do not need to be cut to form grooves, nor do they require a filling process. This can result in a process pipe coating that is both time-efficient and cost-effective. In some embodiments, the coating system 14 comprises a modified cross die 40. In other embodiments, the coating system comprises a different method of applying polyolefin, for example, a side extruder. In the case of a cross die, the die can be configured to allow the passage of the elongated member through the cross die. Example 1: Tube and manufacturing method A steel pipe, pre-coated with a 3-layer polystyrene anti-corrosion coating (consisting of a fusion-bonded epoxy layer closest to the steel of the pipe, followed by a polystyrene adhesive, and then a top polystyrene coating), is fed in a straight line, where the polystyrene anti-corrosion coating is preheated before passing through the cross die. Three polypropylene pipe lines are fed from reels through the cross die at the same time and speed as the 3-layer polystyrene-coated pipe and are aligned in place, spaced equidistantly around and parallel to the pipe, just before entering the cross die. In this way, the three polypropylene pipe lines pass through the die at the same time as the pipe, close to the pipe, and are coated simultaneously as the pipe passes through the die.Cold circulating air is fed into the polypropylene pipe to keep the channel open. As the tube (and polypropylene tubing) passes through the die, the die applies a polystyrene foam insulating material to surround both the tube and the polypropylene tubing. Optionally, the cross die also co-extrudes an external polystyrene top liner. The polystyrene foam insulation and the external polystyrene top sheath are allowed to cool, and the length of pipe is tested for hydrostatic pressure resistance. The pipe length is found to withstand at least 1500 meters of water depth at a maximum system operating temperature of 100°C, with the polypropylene pipe providing channels within the polystyrene foam insulation that do not collapse under that pressure. Example 2: Tube and Manufacturing Method A steel tube, pre-coated with a 3-layer polystyrene anti-corrosion coating (consisting of a fusion-bonded epoxy layer closest to the steel of the tube, followed by a polystyrene adhesive, and then a top polystyrene coating), is fed in a straight line, where the polystyrene anti-corrosion coating is preheated before passing through a cross die. Three lines of hollow tubular steel pipe are fed from reels, through the cross die, at the same time and speed as the 3-layer polystyrene-coated tube, and are aligned in place, spaced equidistantly around and parallel to the 3-layer polystyrene-coated tube, just before entering the cross die. Simultaneously, three lines of aluminum "saddle" are fed, one between each of the steel pipe and the tube.The saddles are solid pieces of aluminum, thin and flexible enough to be fed by a reel. They are configured so that the "top" of the saddle, closest to the steel pipe, is generally shaped to the pipe, and the "bottom" of the saddle, closest to the pipe, is shaped to the tube. Three lines of polypropylene pipe and the three saddles pass through the die at the same time as the pipe, close to the pipe, and are coated simultaneously as the pipe passes through the die. As the tube, saddles, and piping pass through the die, it applies a polystyrene foam insulating material to surround them. Optionally, the cross die also co-extrudes an external polystyrene top liner. The polystyrene foam insulation and the external polystyrene top lining were allowed to cool, and the length of pipe was tested for hydrostatic pressure resistance. The pipe length was found to withstand at least 1500 meters of water depth at a maximum system operating temperature of 100°C, with the steel pipe providing channels within the polystyrene foam insulation that did not collapse under that pressure.

Claims

1. A method of coating a pipe section, the method being characterized in that it comprises: displacing the pipe section longitudinally through a coating system; displacing at least one elongated member through the coating system concurrently with the pipe section; applying a circumferential coating layer by means of the coating system to the pipe section, wherein at least one elongated member is embedded within the circumferential coating layer.

2. The method according to claim 1, further characterized in that the coating layer is an anti-corrosion layer, a polyolefin layer, or an insulating layer.

3. The method according to claim 2, further characterized in that it additionally comprises applying at least one additional layer before the overlay of the coating layer.

4. The method according to claim 3, further characterized in that the coating layer is a polyolefin layer and at least one additional layer comprises an anti-corrosion layer applied before the coating layer.

5. The method according to claim 3, further characterized in that the coating layer is a polyolefin layer and at least one additional layer comprises an insulating layer applied over the coating layer.

6. The method according to claim 3, further characterized in that the coating layer is an insulating layer and at least one additional layer comprises an anti-corrosion layer applied before the coating layer.

7. The method according to claim 3, further characterized in that the coating layer is an insulating layer and at least one additional layer comprises a polyolefin layer applied before the coating layer.

8. The method in accordance with any of the preceding claims, further characterized in that it additionally comprises applying a top coating layer over the coating layer or insulating layer.

9. The method according to claim 4 or 6, further characterized in that the anti-corrosion layer applied before the coating layer is of variable thickness, having a thinner coating in areas where at least one elongated member is to be placed and a thicker coating in areas where no elongated member is to be placed.

10. The method according to claim 4 or 6, further characterized in that the anti-corrosion layer applied before the coating layer is thermally conductive and electrically insulating.

11. The method in accordance with any of the preceding claims, wherein the elongated member is a solid rod.

12. The method in accordance with any of the preceding claims, further characterized in that it additionally comprises: removing at least one elongated member from the lining layer to form at least one channel therein.

13. The method according to claim 12, further characterized in that the removal includes applying a force to displace the elongated member from the coating layer.

14. The method according to any of claims 1 to 10, further characterized in that the elongated member has a continuous cross-section and at least one internal channel.

15. The method according to claim 14, further characterized in that the elongated member is a tubular rod.

16. The method according to claim 14, further characterized in that an additional elongated member with a continuous cross-section is also embedded between the elongated member and the underlying tube or layer.

17. The method according to claim 16, further characterized in that the additional elongated member is made of a material that is the same as or similar to that of the elongated member.

18. The method according to claim 16, further characterized in that the additional elongated member is made of a material with high thermal conductivity.

19. The method according to any of claims 16 to 18, further characterized in that the additional elongated member has a cross-sectional shape which increases the contact surface area between the elongated member and the underlying tube or layer.

20. The method according to any of claims 14 to 19, further characterized in that the elongated member is made of a material that is the same as or similar to that of the coating layer.

21. The method according to any of claims 14 to 19, further characterized in that the elongated member is made of a polymeric composition with preferably increased thermal conductivity.

22. The method according to any of claims 14 to 19, further characterized in that the elongated member is made of a reinforced polymer composition for improved mechanical strength.

23. The method according to any of claims 14 to 19, further characterized in that the elongated member is made of a polymer composition with preferably increased thermal conductivity and reinforced for improved mechanical strength.

24. The method according to any of claims 14 to 23, further characterized in that at least one internal channel of the elongated member is filled with pressurized gas when the elongated member is embedded in the coating layer.

25. The method according to claim 24, further characterized in that the pressurized gas is continuously circulated.

26. The method in accordance with any of claims 24 and 25, further characterized in that the pressurized gas is cooled.

27. The method in accordance with any of claims 1 to 26, further characterized in that the elongated member is metallic.

28. The method in accordance with any of claims 1 to 10, further characterized in that the elongated member is an electrically conductive cable.

29. The method according to claim 28, further characterized in that an additional elongated member with a continuous cross-section is also embedded between the elongated member and the underlying tube or layer.

30. The method according to claim 29, further characterized in that the additional elongated member is made of a material with high thermal conductivity.

31. The method according to any of claims 1 to 30 further characterized in that the circumferential coating is a thermoplastic.

32. The method according to any of claims 1 to 31, further characterized in that the coating system is or comprises a cross die.

33. The method according to claim 32, further characterized in that the cross die is formed to allow passage of the elongated member.

34. The method according to any of claims 1 to 31, further characterized in that the coating system is or comprises a side extruder.

35. The method according to any of claims 1 to 34, further characterized in that the displacement of the tube section through the coating system also includes rotating the tube section.

36. The method according to any of claims 12 to 27 and 32 to 35, further characterized in that it additionally comprises: placing at least one of the heating wires, fiber optic cables or sensors inside the channel.

37. The method in accordance with any of claims 12 to 36, further characterized in that the electrically conductive channel or cable is parallel to the tube section.

38. The method according to any of claims 12 to 36, further characterized in that the electrically conductive channel or cable is helical around the tube section.

39. A multi-layered coated steel tube, further characterized in that it comprises: a. an inner steel tube; b. an outer layer of thermal insulation that resists hydrostatic pressure; c. at least one elongated member embedded within the thermal insulation, having a continuous cross-section.

40. The multi-layered coated steel tube according to claim 39, further characterized in that the continuous cross-section is formed to increase the surface contact area with the inner steel tube.

41. The multi-layered coated steel tube according to any of claims 39 to 40, further characterized in that the outer thermal insulation layer is capable of withstanding more than 1 MPa of hydrostatic pressure.

42. The multi-layered coated steel tube according to claim 41, further characterized in that the outer thermal insulation layer is capable of withstanding more than 5 MPa of hydrostatic pressure.

43. The multi-layered coated steel tube according to claim 42, further characterized in that the outer thermal insulation layer is capable of withstanding more than 10 MPa of hydrostatic pressure.

44. The multi-layered coated steel tube according to claim 43, further characterized in that the outer thermal insulation layer is capable of withstanding more than 30 MPa of hydrostatic pressure.

45. The multi-layered coated steel tube according to any of claims 39 to 44, further characterized in that it additionally comprises at least one additional layer below or above the thermal insulation layer.

46. ​​The multi-layered coated steel tube according to claim 45, further characterized in that at least one additional layer comprises an anti-corrosion layer under the thermal insulation layer.

47. The multi-layered coated steel tube according to any of claims 45 and 46, further characterized in that at least one additional layer further comprises one or more additional thermal insulation layers.

48. The multi-layered coated steel tube according to any of claims 45 to 47, further characterized in that it additionally comprises an outer top coating layer.

49. The multi-layered coated steel tube according to any of claims 46 to 48, further characterized in that the anti-corrosion layer is preferably thinned in the areas between the elongated member and the inner steel tube.

50. The multi-layered coated steel tube according to any of claims 46 to 49, further characterized in that the anti-corrosion layer consists or partially consists of a material which is preferably thermally conductive and electrically insulating.

51. The multi-layered coated steel tube according to any of claims 39 to 50, further characterized in that the elongated member is made of a material that is the same as or similar to the thermal insulation.

52. The multi-layered coated steel tube according to any of claims 39 to 51, further characterized in that the elongated member is made of a polymer composition with preferably increased thermal conductivity.

53. The multi-layered coated steel tube according to any of claims 39 to 52, further characterized in that the elongated member is made of a reinforced polymer composition for improved mechanical strength.

54. The multi-layered coated steel tube according to any of claims 39 to 50, further characterized in that the elongated member is metallic.

55. The multi-layered coated steel tube according to any of claims 39 to 54, further characterized in that the elongated member has at least one internal channel.

56. The multi-layered coated steel tube according to any of claims 39 to 50, further characterized in that the elongated member is an electrically conductive cable.

57. The steel tube coated with multiple layers in accordance with any of claims 39 to 56, further characterized in that the outer thermal insulation layer is a thermoplastic.

58. A multi-layered coated steel tube, characterized in that it comprises: a. an inner steel tube; b. an outer layer of thermal insulation resistant to hydrostatic pressure; c. at least one elongated member embedded within the thermal insulation, with a continuous cross-section; d. an additional elongated member with a continuous cross-section located between each of at least one of the elongated members and the inner steel tube.

59. The multi-layered coated steel tube according to claim 58, further characterized in that the additional elongated member is formed to increase the surface contact area between the elongated member and the inner steel tube.

60. The multi-layered coated steel tube according to any of claims 58 to 59, further characterized in that the outer thermal insulation layer is capable of withstanding hydrostatic pressure of at least 1 MPa.

61. The multi-layered coated steel tube according to claim 60, further characterized in that the outer layer of thermal insulation is capable of withstanding hydrostatic pressure of at least 5 MPa.

62. The multi-layered coated steel tube according to claim 61, further characterized in that the outer thermal insulation layer is capable of withstanding hydrostatic pressure of at least 10 MPa.

63. The multi-layered coated steel tube according to claim 62, further characterized in that the outer layer of thermal insulation is capable of withstanding hydrostatic pressure of at least 30 MPa.

64. The multi-layered coated steel tube according to any of claims 58 to 63, further characterized in that it additionally comprises at least one additional layer below or above the thermal insulation layer.

65. The multi-layered coated steel tube according to claim 64, further characterized in that at least one additional layer comprises an anti-corrosion layer under the thermal insulation layer.

66. The multi-layered coated steel tube according to claim 64 or 65, further characterized in that at least one additional layer further comprises one or more additional layers of thermal insulation.

67. The multi-layered coated steel tube according to any of claims 58 to 66, further characterized in that it further comprises an outer top coating layer.

68. The multi-layered coated steel tube according to any of claims 58 to 67, further characterized in that the anti-corrosion layer is preferably thinned in the areas between the elongated member and the inner steel tube.

69. The multi-layered coated steel tube according to any of claims 58 to 68, further characterized in that the anti-corrosion layer consists or partially consists of a material which is preferably thermally conductive and electrically insulating.

70. The multi-layered coated steel tube according to any of claims 58 to 69, further characterized in that at least one elongated member is made of a material that is the same as or similar to the thermal insulation.

71. The multi-layered coated steel tube according to any of claims 58 to 70, further characterized in that at least one elongated member is made of a polymer composition with preferably increased thermal conductivity.

72. The multi-layered coated steel tube according to any of claims 58 to 71, further characterized in that at least one elongated member is made of a reinforced polymer composition for improved mechanical strength.

73. The multi-layered coated steel tube according to any of claims 58 to 70, further characterized in that at least one elongated member is metallic.

74. The multi-layered coated steel tube according to any of claims 58 to 73, further characterized in that the elongated member has at least one internal channel.

75. The multi-layered coated steel tube according to any of claims 58 to 69, further characterized in that at least one elongated member is an electrically conductive cable.

76. The multi-layered coated steel tube according to any of claims 58 to 74, further characterized in that the additional elongated member is made of the same or similar material to at least one elongated member.

77. The multi-layered coated steel tube according to any of claims 58 to 74, further characterized in that the additional elongated member has a higher thermal conductivity than at least one elongated member.

78. The steel tube coated with multiple layers in accordance with any of claims 58 to 77, further characterized in that the outer thermal insulation layer is a thermoplastic.