Assembly comprising an end-fitting and an unbonded flexible pipe

Patent metadata

Field	Value
Publication number	US-10655772-B2
Application number	US-201515516695-A
Country	US
Kind code	B2
Filing date	Oct 14, 2015
Priority date	Oct 20, 2014
Publication date	May 19, 2020
Grant date	May 19, 2020

Abstract

The present invention relates to an assembly including an end-fitting and an unbonded flexible pipe, which end-fitting is adapted for connecting the unbonded flexible pipe to a connector. The end-fitting has a through-going opening with a centerline and a front end and a rear end, and the end-fitting further provides for establishing an electrical connection to a least one electrical heating system in the unbonded flexible pipe. Moreover, the end-fitting includes at least one first metallic part having a first surface contacting a second surface of at least one second part in the end-fitting, wherein the first surface of the first metallic part, at least in the vicinity of the through-going opening, includes a coating having a high electrically resistivity. The invention also relates to a method for providing an end-fitting having good properties in respect of reducing galvanic corrosion.

First claim

What is claimed is:

1. An assembly comprising:
an end-fitting and an unbonded flexible pipe, said end-fitting being adapted for connecting the unbonded flexible pipe to a connector, said end-fitting having a through-going opening with a centerline and a front end and a rear end, said rear end comprising a flange including a rear-most end face, and said end-fitting further comprising means for establishing an electrical connection to a least one electrical heating system in said unbonded flexible pipe,
wherein said end-fitting comprises at least one first metallic part having the rear-most end face and having a first surface contacting a second surface of at least one second part in the end-fitting,
the at least one first metallic part being electrically insulated from the at least one electrical heating system,
wherein the first surface of the first metallic part includes a portion at and defining the through-going opening having a coating having a high electrically resistivity of at least 10 7 Ω·m.

2. An assembly according to claim 1 , wherein the second part is a metallic part and said second surface comprises a coating having a high electrically resistivity, and wherein said second part is axially spaced from the rear-most end face.

3. An assembly according to claim 1 , wherein at least a part of the coating comprises a bushing.

4. An assembly according to claim 1 , wherein the second part is a non-metallic part.

5. An assembly according to claim 1 , wherein the second part is an electrical insulating part.

6. An assembly according to claim 1 , wherein the electrical heating system comprises one or more armour layers selected among carcass, tensile armour and pressure armour.

7. An assembly according to claim 6 , wherein the one or more armour layers are axially spaced from the rear-most end face.

8. An assembly according to claim 1 , wherein the electrical heating system comprises one or more wires.

9. An assembly according to claim 1 , wherein the coating is selected from an epoxy coating, a polyurethane coating, a polytetrafluoroethylene coating, a fluorinated ethylene propylene coating, a polyvinyl chloride coating, an enamel coating, a ceramic coating, a glass coating and combinations thereof.

10. An assembly according to claim 1 , wherein the coating is applied with a thickness from about 0.05 mm to about 5 mm.

11. An assembly according to claim 1 , wherein the end-fitting comprises an insulating coating on the outer surface.

12. An assembly according to claim 1 , wherein the end-fitting comprises a protective sleeve.

13. An assembly according to claim 1 , wherein the end-fitting is housed in an electrical insulating housing.

14. An assembly according to claim 1 , wherein said at least one electrical heating system is axially spaced from the rear-most end face.

15. An assembly according to claim 1 , wherein said at least one electrical heating system includes at least a pair of wires extending radially through the end-fitting to an outer surface of the end-fitting, the pair of wires being insulated from the end-fitting, and the end-fitting configured to allow connection of each wire of the pair of wires to an armour layer of the flexible pipe while insulating the end-fitting therefrom.

16. A method for reducing the risk of galvanic corrosion in an end-fitting for connecting an unbonded flexible pipe comprising electrical heating means to a connector, said method comprises:
providing an end-fitting having a flange and a through-going opening with a centerline and a front end and a rear end, said rear end including a rear-most end face, and the end-fitting comprising means for establishing an electrical connection to the heating means in said unbonded flexible pipe, said end-fitting comprises at least one first metallic part having the rear-most end face and having a first surface adapted for contacting a second surface of at least one second part in the end-fitting and having a portion of the first surface disposed at and defining the through-going opening;
subjecting the first surface and the second surface of the first metallic part for a treatment to obtain a substantially clean surface;
applying a coating having a high electrical resistance to the cleaned first surface and the cleaned second surface; and
curing the applied coating to obtain a coating being an electrically insulating coating having an electrically resistivity of at least 10 7 Ω·m,
wherein the end-fitting includes at least the first metallic part being electrically insulated from the heating means.

17. A method according to claim 16 , wherein the second surface of the second part is subjected to a treatment to obtain a substantially clean second surface and applying the clean second surface with a coating having a high electrical resistance.

18. A method according to claim 16 , wherein the coating is selected from an epoxy coating, a polyurethane coating, a polytetrafluoroethylene coating, a fluorinated ethylene propylene coating, an enamel coating and combinations thereof.

19. A method according to claim 16 , wherein treatment of the surface is a sand blasting, a mechanical cleaning, a chemical etching, an electro polishing or a combination of two or more of the mentioned treatments.

20. A method according to claim 16 , comprising the further step of applying an adhesive layer to the cleaned surface.

21. An assembly comprising:
an end-fitting and an unbonded flexible pipe, said end-fitting being adapted for connecting the unbonded flexible pipe to a connector, said end-fitting having a through-going opening with a centerline and a front end and a rear end, said rear end comprising a flange including a rear-most end face, and said end-fitting further comprising means for establishing an electrical connection to a least one electrical heating system in said unbonded flexible pipe,
wherein said end-fitting comprises at least one first metallic part having the rear-most end face and having a first surface contacting a second surface of at least one second part in the end-fitting, the at least one first metallic part being electrically insulated from the at least one electrical heating system,
wherein the first surface of the first metallic part includes a portion at and defining the through-going opening-having a coating having a high electrically resistivity of at least 10 7 am, and
wherein the unbonded flexible pipe enters the end-fitting at the front end and is terminated in the end-fitting and wherein said first surface of the first metallic part defining the through-going opening is located further away from the unbonded flexible pipe than the means for establishing an electrical connection.

Assignees

• Nat Oilwell Varco Denmark Is

Inventors

• Larsen Tom
• Holst Thorsten

Classifications

• F16L11/12

  with arrangements for particular purposes, e.g. specially profiled, with protecting layer, heated, electrically conducting (F16L11/11 takes precedence) · CPC title

• F16L33/01

  specially adapted for hoses having a multi-layer wall · CPC title

• B23P19/047

  for flexible profiles, e.g. sealing or decorating strips in grooves or on other profiles by devices moving along the flexible profile (hand tools therefor B25B27/0092) · CPC title

• F16L53/38 Primary

  using elongate electric heating elements, e.g. wires or ribbons · CPC title

• F16L53/34

  using electric, magnetic or electromagnetic fields, e.g. induction, dielectric or microwave heating · CPC title