Flexible pipe having a multi-layered structure
AssigneeEvonik Degussa GmbH
InventorsKarl Kuhmann, Andreas Dowe, Rainer Goering
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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.
Claims8
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).
Dependencies are inferred from the claim text.