Flexible pipe having a multi-layered structure

Patent metadata

Field	Value
Publication number	US-9314989-B2
Application number	US-201113640552-A
Country	US
Kind code	B2
Filing date	Mar 18, 2011
Priority date	Apr 13, 2010
Publication date	Apr 19, 2016
Grant date	Apr 19, 2016

Abstract

The invention relates to a flexible pipe having a multi-layered structure comprising unbonded layers, comprising an inner lining having the following layer arrangement: a) an innermost layer made of a fluoropolymer molding compound, b) an intermediate layer made of a molding compound on the basis of an olefinic polymer, which is selected from the group consisting of polyethylene, isotactic polypropylene, syndiotactic polypropylene and syndiotactic polystyrene, c) an outer layer made of a polyamide molding compound, wherein the layer made of a polyamide molding compound is particularly efficiently protected against hydrolysis. The pipe is thus particularly suited for offshore applications in oil or gas production.

First claim

The invention claimed is:

1. A flexible pipe of multilayer structure with at least two unbonded layers, said pipe comprising an inner lining comprising layers a), b) and c) following one another directly,
wherein:
a) is an innermost layer comprising a fluoropolymer molding composition;
b) is an intermediate layer comprising a molding composition comprising an olefinic polymer selected from the group consisting of polyethylene, isotactic polypropylene, syndiotactic polypropylene and syndiotactic polystyrene; and
c) is an outer layer comprising a polyamide molding composition; and
the flexible pipe with the inner lining comprising a), b) and c) provides improved protection from diffusion of water from the fluid being conveyed through the pipe and improved service life at operating temperatures above 70° C. relative to a flexible pipe with an inner lining of the same thickness comprising layers a) and c) without b) and an inner lining of the same thickness comprising layers b) and c) without a).

2. The flexible pipe of claim 1 , wherein the inner lining is a pipe.

3. The flexible pipe of claim 2 , further comprising one or more layers selected from the group consisting of
an inner carcass,
an outer reinforcing layer, and
an outer shell.

4. The flexible pipe of claim 1 , further comprising one or more layers selected from the group consisting of
an inner carcass,
an outer reinforcing layer, and
an outer shell.

5. The flexible pipe of claim 1 , wherein the polyamide comprising the polyamide molding composition of outer layer c) is a polyether amide.

6. The flexible pipe of claim 1 , wherein the thickness of the innermost layer a) of the fluoropolymer molding composition is 1 to 20% of the total wall thickness of the inner lining, the thickness of the intermediate layer b) of the molding composition based on an olefinic polymer is 2 to 50% of the total wall thickness of the inner lining, and the thickness of the outer layer c) of the polyamide molding composition is 20 to 97% of the total wall thickness of the inner lining.

7. The flexible pipe of claim 1 , wherein the monomer units of the polyamide contain an average of at least 8 carbon atoms.

8. The flexible pipe of claim 1 , wherein the polyethylene comprising the molding composition of intermediate layer b) is high density polyethylene.

Assignees

• Kuhmann Karl
• Dowe Andreas
• Goering Rainer
• Evonik Degussa Gmbh

Inventors

• Kuhmann Karl
• Dowe Andreas
• Goering Rainer

Classifications

• F16L11/081 Primary

  comprising one or more layers of a helically wound cord or wire (in combination with braided layers F16L11/088) · CPC title

• B32B1/08 Primary

  Tubular products · CPC title

• B32B2307/546

  Flexural strength; Flexion stiffness · CPC title

• B32B27/28

  comprising synthetic resins not wholly covered by any one of the sub-groups {B32B27/30 - B32B27/42} · CPC title

• B32B27/34

  comprising polyamides · CPC title