IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0089321
(2006-10-10)
|
등록번호 |
US-8302634
(2012-11-06)
|
우선권정보 |
DK-2005 01422 (2005-10-11) |
국제출원번호 |
PCT/DK2006/050056
(2006-10-10)
|
§371/§102 date |
20080404
(20080404)
|
국제공개번호 |
WO2007/042049
(2007-04-19)
|
발명자
/ 주소 |
|
출원인 / 주소 |
- National Oilwell Varco Denmark I/S
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
0 인용 특허 :
8 |
초록
▼
The invention relates to a method of producing a flexible pipe comprising a metal carcass and an internal sealing sheath extruded onto the carcass, said 5 method comprising providing a metal carcass; heating an application section of said carcass, preferably using induction heating, to an applicatio
The invention relates to a method of producing a flexible pipe comprising a metal carcass and an internal sealing sheath extruded onto the carcass, said 5 method comprising providing a metal carcass; heating an application section of said carcass, preferably using induction heating, to an application section temperature of at least 150° C.; extruding a non-cross-linked polyethylene material comprising a peroxide having an activation temperature above 150° C. onto said application section of said carcass; cross-linking the extruded 10 polyethylene in a cross-linking zone by raising its temperature to at least the activation temperature of said peroxide by exposing the extruded polymer material to electromagnetic waves, with a wavelength of between 0.5 μm to 0.5 m, preferably infrared radiation; and cooling said cross-linked polyethylene material to obtain the internal sealing sheath. 15 In a preferred embodiment the method comprises heating the application section to an application section temperature of between 30 and 5° C. below the activation temperature of the peroxide. 20 Preferred peroxides include butylcumyl peroxide, dicumyl peroxide, 2,5-Dimethyl-2,5-di(tert-butylperoxy)hexyne-3,3,3,5,7,7-Pentamethyl-1,2,4-trioxepane, hydroperoxide, 2,5-dimethyl hexane 2,5-di-t-butyl peroxide, bis(t-butylperoxy isopropyl)benzene, t-butyl cumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl hexine-3 2,5-di-t-butyl peroxide and butylhydroperoxide. 25 A foil may be applied onto the metal carcass prior to the step of heating the metal carcass, the polyethylene material being extruded onto said foil. 30
대표청구항
▼
1. A method of producing a flexible pipe comprising a metal carcass and an internal sealing sheath extruded onto the carcass, said method comprising the steps of providing a metal carcass;heating an application section of said carcass to an application section temperature of at least about 150° C.;e
1. A method of producing a flexible pipe comprising a metal carcass and an internal sealing sheath extruded onto the carcass, said method comprising the steps of providing a metal carcass;heating an application section of said carcass to an application section temperature of at least about 150° C.;extruding a non-cross-linked polyethylene material comprising a peroxide having an activation temperature above about 150° C. onto said application section of said carcass;cross-linking the extruded polyethylene in a cross-linking zone by raising its temperature to at least the activation temperature of said peroxide by exposing the extruded polymer material to electromagnetic waves, with a wavelength of between about 0.5 μm to about 0.5 m; andcooling said cross-linked polyethylene material to obtain the internal sealing sheath. 2. A method as claimed in claim 1 wherein the application section of said metal carcass is heated to the application temperature using induction heating. 3. A method as claimed in claim 2 wherein the induction heating is provided by a coil placed at a distance along the length of the carcass to an extrusion head extruding the polyethylene material which distance is less than about two times the extrusion length per minute. 4. A method as claimed in claim 2 wherein the induction heating is provided by a coil placed at a distance along the length of the carcass to an extrusion head extruding the polyethylene material which distance is about 200 cm or less. 5. A method as claimed in claim 1 wherein the carcass section onto which the polyethylene material has been extruded is not subjected to further heating using induction heating. 6. A method as claimed in claim 1 wherein said metal carcass is of steel. 7. A method as claimed in claim 1 wherein said metal carcass is a flexible tube provided by one or more helically wound and interlocked profiles. 8. A method as claimed in claim 1 wherein said step of heating the application section of the metal carcass comprises heating the application section to an application section temperature of at least about 155° C. 9. A method as claimed in claim 1 wherein said step of heating the application section of the metal carcass comprises heating the application section to an application section temperature of between about 30° C. and about 5° C. below the activation temperature of the peroxide. 10. A method as claimed in claim 1 wherein said step of heating the application section of the metal carcass comprises heating the application section to an application section temperature of at least about the melting point of the extruded not-cross-linked polyethylene material. 11. A method as claimed in claim 1 wherein said polyethylene material has a density of at least about 920 g/cm3. 12. A method as claimed in claim 1 wherein said polyethylene material prior to extrusion comprises at least about 70% by weight of polyethylene. 13. A method as claimed in claim 1 wherein said polyethylene material comprises up to about 10% by weight of fillers. 14. A method as claimed in claim 1 wherein said polyethylene material prior to extrusion comprises up to about 30% by weight of additional polymer(s) other than polyethylene. 15. A method as claimed in claim 1 wherein the amount of peroxide in the polymer material is at least about 0.1% by weight of the polyethylene material. 16. A method as claimed in claim 15 wherein the amount of peroxide in the polymer material is between about 0.1% and about 1.0% by weight. 17. A method as claimed in claim 1 wherein the peroxide has an activation temperature above about 150° C. 18. A method as claimed in claim 1 wherein the peroxide is selected from butylcumyl peroxide, dicumyl peroxide, 2,5-Dimethyl-2,5-di(tert-butylperoxy)hexyne-3,3,3,5,7,7-Pentamethyl-1,2,4-trioxepane, hydroperoxide, 2,5-dimethyl hexane 2,5-di-t-butyl peroxide, bis(t-butylperoxy isopropyl)benzene, t-butyl cumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl hexine-3 2,5-di-t-butyl peroxide, butylhydroperoxide and mixtures thereof. 19. A method as claimed in claim 18, wherein the peroxide is 3,3,5,7,7-Pentamethyl-1,2,4-trioxepane. 20. A method as claimed in claim 1 wherein the cross-linking is activated by exposing the extruded polyethylene material to electromagnetic waves with a wavelength measured in vacuum of between about 0.5 μm and about 20 cm. 21. A method as claimed in claim 20 wherein the cross-linking is activated by application of infrared radiation. 22. A method as claimed in claim 1 wherein the pressure in the cross-linking zone is raised to avoid formation of bubbles and irregularities. 23. A method as claimed in claim 1 wherein the extruded polyethylene material is subjected to a treatment with infrared radiation in said cross-linking zone, the temperature of the polyethylene material being raised to above about 150° C. 24. A method as claimed in claim 1 wherein the average degree of cross-linking of the polyethylene material obtained is at least about 85%. 25. A method as claimed in claim 1 wherein the average degree of cross-linking of the polyethylene material obtained in the cross-linked internal sheath, excluding an inner and an outer layer of 0.3 mm is at least about 91%. 26. A method as claimed in claim 1 wherein the extrusion and cross-linking steps are carried out in an in-line process, including passing the metal carcass with a delivery velocity through a heating zone wherein the application section of the metal carcass is heated, though an extrusion zone wherein the polyethylene material is extruded onto the metal carcass, to the cross-linking zone wherein the polyethylene material is cross-linked. 27. A method as claimed in claim 26 wherein the feeding velocity is between about 0.1 m/minute and about 2 m/minute. 28. A method as claimed in claim 26 wherein the distance between the metal carcass heating zone and the extrusion zone is less than about two times the feeding velocity. 29. A method as claimed in claim 26 wherein the distance between the extrusion zone and the cross-linking zone is less than about two times the feeding velocity. 30. A method as claimed in claim 26 wherein the heating zone has a length of between about 10 cm and about 500 cm. 31. A method as claimed in claim 26, wherein a vacuum is applied inside the carcass to calibrate the extruded polymer layer towards the carcass. 32. A method as claimed in claim 1 further comprising the step of applying a foil onto the metal carcass prior to the step of heating the metal carcass, the polyethylene material being extruded onto said foil. 33. A method as claimed in claim 32 wherein the foil has a thickness of up to about 2 mm. 34. A method as claimed in claim 32 wherein the foil is wound or folded onto the carcass. 35. A method as claimed in claim 32 wherein the foil is of a material selected from a metal and a polymer. 36. A method as claimed in claim 1 wherein the polyethylene material is extruded with a thickness of about 4 mm or more. 37. A method as claimed in claim 1 wherein the cross-linked polyethylene material is cooled in the cooling step by water cooling. 38. A method as claimed in claim 37 wherein the cross-linked polyethylene material is passed from the cross-linking zone and through a water bath cooling the cross-linked polyethylene material from its outer side. 39. A method as claimed in claim 1 further comprising the step of applying additional layers onto the internal sealing sheath wherein at least one of the additional layers is not bonded to another layer of the flexible pipe.
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