초록 ▼

Apparatus for heating and lagging at least one main undersea pipe for conveying a flow of hot effluent. The apparatus includes a covering of thermally insulating material surrounding the main pipe(s), and covered by a leaktight outer protective casing and an internal chamber coaxial with the outer c

Apparatus for heating and lagging at least one main undersea pipe for conveying a flow of hot effluent. The apparatus includes a covering of thermally insulating material surrounding the main pipe(s), and covered by a leaktight outer protective casing and an internal chamber coaxial with the outer casing. The insulating covering surrounds the internal chamber in an annular space between the outer casing and the internal chamber. The main pipe is contained inside an internal chamber that is preferably cylindrical in shape. A heat-transfer fluid having a maintained temperature surrounds the main pipe contained inside the internal chamber and is circulated inside the internal chamber.

대표청구항 ▼

The invention claimed is: 1. Apparatus for heating and lagging at least one undersea main bottom-to-surface connection pipe for carrying a flow of hot effluent, the apparatus comprising: a covering of at least one thermally insulating material surrounding said at least one main pipe; said insulatin

The invention claimed is: 1. Apparatus for heating and lagging at least one undersea main bottom-to-surface connection pipe for carrying a flow of hot effluent, the apparatus comprising: a covering of at least one thermally insulating material surrounding said at least one main pipe; said insulating covering being covered by a leaktight outer protective casing; an internal chamber with a solid wall of cylindrical shape and coaxially disposed inside said outer casing, such that: said insulating covering surrounds said internal chamber and is disposed within an annular space between said outer casing and said internal chamber; said at least one main pipe is contained inside said internal chamber; and said heat-transfer fluid surrounds said at least one main pipe and circulates longitudinally between both longitudinal extremities of said internal chamber; and means suitable for maintaining the temperature of a heat-transfer fluid and for causing it to circulate inside said internal chamber. 2. Apparatus according to claim 1, wherein said internal chamber conveys at least one internal gas-injection pipe suitable for enabling gas to be injected into said main pipe, said internal gas-injection pipe being connected to said main pipe at one end in the longitudinal direction of said main pipe inside said internal chamber, and said gas-injection pipe extending outside said internal chamber in the form of an external gas-injection pipe connecting said internal gas-injection pipe to a floating support. 3. Apparatus according to claim 1, wherein said fluid-circulation means for circulating a heat-transfer fluid comprise at least one internal heat-transfer fluid feed pipe extending in the longitudinal direction inside said internal chamber from a first orifice situated at a first end of the internal chamber, as far as the vicinity of the second end of said internal chamber, and a second orifice for outlet of said heat-transfer fluid, said internal heat-transfer fluid feed pipe being situated beside said main pipe, between it and said outer insulating material. 4. Apparatus according to claim 2, wherein said internal gas-injection pipe is a pipe that is spiral-wound around said internal heat-transfer fluid feed pipe inside said internal chamber. 5. Apparatus according to claim 3, wherein said internal heat-transfer fluid feed pipe is extended from said first orifice to a floating support by an external flexible pipe for feeding said heat-transfer fluid, and said second orifice for outlet of heat-transfer fluid is connected to a second external flexible pipe for returning said heat-transfer fluid to said floating support. 6. Apparatus according to claim 3, wherein said internal heat-transfer fluid feed pipe is connected to heat-transfer fluid circulation means comprising a pump co-operating at said first end of the internal chamber with said first orifice for feeding heat-transfer fluid and with said second orifice for outlet of heat-transfer fluid, said pump enabling the heat-transfer fluid to be circulated successively inside said internal heat-transfer fluid feed pipe, then inside the internal chamber, then out from said internal chamber via said second orifice, and finally recirculating in a loop back into said internal chamber via said first orifice, an external flexible pipe for circulating heat-transfer fluid providing a connection between said floating support and the body of the pump or said first orifice. 7. Apparatus according to claim 6, further comprising a heater means for heating the heat-transfer fluid inside said internal heat-transfer fluid feed pipe. 8. Apparatus according to claim 1, further comprising at least one transverse end partition at least a said first end, said end transverse partition supporting said main pipe and also said fluid-circulation means, and having said main pipe passing therethrough and, where appropriate, having first and second orifices enabling said heat-transfer fluid to be caused to circulate inside and outside said internal chamber via said orifices. 9. Apparatus according to claim 8, further comprising first and second transverse end partitions each at a respective one of the two ends of the internal chamber, said first end partition including, where appropriate, said first and second orifices, and said two transverse end partitions supporting said outer casing and said internal chamber and connecting them together in leaktight manner, while also ensuring, at least at a first end, that the heat-transfer fluid is confined inside the internal chamber. 10. Apparatus according to claim 9, wherein said second end partition includes a large orifice of diameter greater than that of the main pipe, through which orifice said main pipe passes, so that the heat-transfer fluid is in contact with sea water at the bottom end of the internal chamber. 11. Apparatus according to claim 9, wherein said second end partition includes an orifice surrounding and secured to a tubular sleeve inside which said main pipe can slide with little clearance. 12. Apparatus according to claim 1, wherein said main pipe is covered in a second insulating covering, at least at said second end of the internal chamber, said heat-transfer fluid circulating in said internal chamber outside said second covering. 13. Apparatus according to claim 12, wherein said second covering is constituted by a thermally insulating material, said solid material directly surrounding said main pipe. 14. Apparatus according to claim 1, wherein said insulating covering comprises an insulating material that is subject to migration, and at least one of said outer casing and said internal chamber is constituted by a solid material that is flexible or semi-rigid and suitable for tracking deformations of the insulating material and for remaining in contact therewith when it deforms. 15. Apparatus according to claim 1, wherein said insulating material is a phase-change material presenting a liquid/solid melting temperature greater than the temperature of the sea water environment surrounding the pipe in operation and less than the temperature above which the effluent flowing inside the pipe presents an increase in viscosity that is damaging for flow thereof in said main pipe. 16. Apparatus according to claim 15, wherein said phase-change insulating material comprises chemical compounds of the alkane family. 17. Apparatus according to claim 1, wherein said insulating material comprises an insulating mixture comprising a first compound consisting in a hydrocarbon compound such as paraffin or gas oil, mixed with a second compound consisting in a gelling compound and/or a compound having a structuring effect, in particular by cross-linking, such as a second compound of the polyurethane type, cross-linked polypropylene, cross-linked polyethylene, or silicone. 18. Apparatus according to claim 1, wherein said insulating covering comprises at least one said viscous solid material that is subject to migration and at least two intermediate transverse partitions that are leaktight, each of said intermediate transverse partitions being constituted by a closed rigid structure having said internal chamber passing therethrough and secured to the walls of said internal chamber and to said outer casing. 19. Apparatus according to claim 18, further comprising at least one centralizing template disposed at regular intervals between two of said leaktight intermediate transverse partitions in succession along said longitudinal axis, each centralizing template being constituted by a rigid piece secured to at least one of the wall of the internal chamber and of said outer casing, and presenting a shape which allows limited displacement of said outer casing or respectively of said internal chamber in contraction and in expansion facing said centralizing template, at least said outer casing or respectively said internal chamber being made of a material that is flexible or semi-rigid and suitable, where appropriate, for remaining in contact with the insulating covering when it deforms. 20. Apparatus according to claim 18, further comprising at least one shaping template constituted by a rigid structure secured to said internal chamber which passes therethrough and secured to said outer casing at its periphery, being disposed between two of said leaktight intermediate transverse partitions that are disposed in succession, each shaping template presenting openings allowing the material constituting said insulating material that is subject to migration to pass through said shaping template. 21. Apparatus according to claim 1, wherein said outer casing and said internal chamber are coaxial along a longitudinal axis and define a perimeter presenting, at rest, two axes of symmetry that are mutually perpendicular and perpendicular to said longitudinal axis, and at least one of the walls constituting said outer casing and/or said internal chamber is made of a material that is flexible or semi-rigid, while the other wall is constituted by a material that is rigid, and more preferably of cross-section that is circular in shape. 22. Apparatus according to claim 21, wherein the cross-section of the outer casing, which is formed of a rigid material is circular in shape, while the cross-section of said internal chamber is oval in shape or rectangular in shape with rounded corners. 23. Apparatus according to claim 21, wherein the cross-section of the internal chamber, which is formed of a rigid material is circular in shape, while the cross-section of the outer casing is oval in shape or rectangular in shape with rounded corners. 24. Apparatus according to claim 1, characterized in that at least one of said main pipe and said internal heat-transfer fluid feed pipe, co-operates inside said internal chamber with centralizing elements which hold said pipes substantially parallel to the axis of said internal chamber while allowing said pipes to move due to differential expansion thereof. 25. Apparatus according to claim 1 for heating and lagging a bundle of undersea main pipes, wherein the apparatus comprises at least two of said main pipes disposed in parallel inside said internal chamber. 26. A bottom-to-surface connection installation between an undersea pipe resting on the sea bottom, in particular at great depth, and a supporting float, the installation comprising: a) at least one vertical riser connected at its bottom end to at least one said undersea pipe resting on the sea bottom, and at its top end to at least one float said vertical riser being included in apparatus according to claim 1, said vertical riser corresponding to said main pipe, and said internal chamber extending over a depth of at least 1000 meters; b) at least one flexible connection pipe connecting the supporting float with the top end of said vertical riser; and c) an external pipe for circulating the heat-transfer fluid between the supporting float and first and second orifices at a first end of the internal chamber, and for injecting gas. 27. An installation according to claim 26, further comprising a second outer casing of circular cross-section secured to said outer protective casing of said lagging and heating apparatus. 28. A method of heating and thermally insulating at least one main undersea pipe providing a bottom-to-surface connection for delivering a flow of hot effluent to or from the bottom of the sea and the surface, the method being a heating and lagging apparatus according to claim 1 is used, and a said heat-transfer fluid is caused to flow inside a said internal chamber. 29. The method according to claim 28, wherein said heat-transfer fluid is selected from sea water, fresh water, gas oil, and oil. 30. The method according to claim 28, wherein said main pipe is heated by said flow of said heat-transfer fluid during a stage of restarting production after a prolonged stoppage.