Insulation of pipe-in-pipe systems

Patent metadata

Field	Value
Publication number	US-11280442-B2
Application number	US-201816956530-A
Country	US
Kind code	B2
Filing date	Dec 17, 2018
Priority date	Dec 20, 2017
Publication date	Mar 22, 2022
Grant date	Mar 22, 2022

Abstract

A pipe-in-pipe section comprises an inner pipe spaced within an outer pipe to define an annulus between the inner and outer pipes. The annulus contains a solid insulating material, which may be a microporous aerogel, and an inert gas such as krypton at near-atmospheric pressure.

First claim

The invention claimed is:

1. A method of filling an initially air-filled annulus of a pipe-in-pipe section with a noble gas comprises:
pressurising the air in the air-filled annulus from an initial pressure to an elevated pressure that is above the initial pressure, the elevated pressure being above 5 bars;
flushing the pressurised annulus with the noble gas; and
after flushing with the noble gas, reducing the pressure in the annulus to an absolute pressure of less than 1.5 bars.

2. The method of claim 1 , wherein the noble gas in the annulus is at an absolute pressure of greater than 0.5 bar.

3. The method of claim 1 , wherein the noble gas in the annulus is substantially at atmospheric pressure.

4. The method of claim 1 , wherein pressure in the annulus is reduced to between 0.5 and 1.5 bars after flushing with the noble gas.

5. The method of claim 1 , wherein the noble gas is krypton.

6. The method of claim 1 , comprising flushing the pressurised annulus until the noble gas is at least a majority, by concentration, of all gases in the annulus.

7. The method of claim 1 , comprising placing a solid insulating material into the annulus before filling the remainder of the annulus with the noble gas.

8. The method of claim 7 , wherein the insulating material is a microporous material.

9. The method of claim 8 , wherein the microporous material has an average pore diameter of less than 100 nm.

10. The method of claim 7 , wherein the insulating material is silica-based.

11. The method of claim 7 , wherein the insulating material is an aerogel.

12. The method of claim 7 , comprising placing the insulating material as an annular layer in continuous contact with the inner pipe.

13. The method of claim 7 , comprising spacing the insulating material from the outer pipe by an annular gap.

Assignees

• Acergy France SAS

Inventors

• Lodeho Olivier
• Wegner Alexis

Classifications

• F16L9/18 Primary

  Double-walled pipes; Multi-channel pipes or pipe assemblies · CPC title

• F16L59/143 Primary

  Pre-insulated pipes · CPC title

• F16L58/04

  Coatings characterised by the materials used (F16L58/16 takes precedence) · CPC title

• E21B33/13

  Methods or devices for cementing, for plugging holes, crevices or the like · CPC title

• F16L59/06

  Arrangements using an air layer or vacuum · CPC title