Bendable Pre-Insulated Pipeline Assembly with Transverse Slits
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Solution Overview
Problem
Existing thermal insulated pipelines for offshore applications are either too rigid and expensive due to the need for a rigid outer casing to withstand high pressures, or they lack sufficient flexibility to be bent and rolled onto reels, leading to increased installation costs and risks of damage during reeling.
Innovation Solution
A pipeline assembly with a closed-cell or solid thermal insulation layer directly or indirectly bonded to both the inner carrier pipe and outer casing, featuring slits transverse to the longitudinal direction to enhance bending properties, allowing for load transfer and reduced material costs by using a less expensive polymer-based coating instead of metal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid outer casing is used to withstand high pressures, then the pipeline can sustain external pressure up to 20 bars or more, but the pipeline becomes too rigid to be bent and rolled onto reels
Solution Approach 1:
The insulation layer is segmented by introducing transverse slits that divide it into multiple segments along the pipeline length. These slits allow the insulation layer to flex and deform during bending without compromising the structural integrity of the rigid outer casing, thus enabling the pipeline to be rolled onto reels while maintaining pressure resistance
Solution Approach 2:
The rigid outer casing maintains its full rigidity and pressure resistance capability, while the insulation layer between the casing and inner pipe is modified with slits to provide local flexibility. This creates a composite structure where different regions have different mechanical properties - the casing remains rigid for pressure containment while the insulated region becomes flexible for bending applications
2Strength
If the outer casing is made of metal to ensure sufficient rigidness, then the pipeline can withstand pressure and transfer loads, but the costs increase due to corrosion treatment requirements
Solution Approach 1:
The outer casing is replaced with a less expensive polymer-based coating that does not require costly corrosion treatment. The transverse slits in the insulation layer compensate for the lower mechanical strength of polymer by providing flexibility, allowing the use of cheaper materials while maintaining functional performance
Solution Approach 2:
The pipeline employs a composite structure combining polymer-based outer casing with a specially designed insulation layer containing transverse slits. This composite design allows the use of cost-effective polymer materials while the slit configuration provides the necessary mechanical properties that would otherwise require expensive metal construction
3Stability of the object's composition
If spacers are placed between the inner and outer tubular to center them and transfer loads, then the tubulars can be centered relative to each other, but the manufacturing process becomes cumbersome, labor intensive and time consuming
Solution Approach 1:
The spacers are completely removed from the pipeline structure. Instead of using separate spacer components to center and support the inner tubular, the insulation layer itself is designed with transverse slits that provide both centering function and load transfer capability, eliminating the need for additional spacer components and simplifying manufacturing
Solution Approach 2:
The insulation layer is given multiple functions: it provides thermal insulation, centers the inner tubular through its slit configuration, transfers loads between tubulars, and enables bending flexibility. This multi-functional design eliminates the need for separate spacer components, streamlining the manufacturing process while maintaining all necessary functions
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The pipeline assembly can be bent without severe fracture, facilitating longer section manufacturing, faster installation, and reduced offshore work, with improved load transfer capabilities and reduced risk of damage during reeling, while maintaining thermal insulation properties.
Implementation Method 1
at least one closed-cell and/or solid thermal insulation material layer placed in between the casing and the inner carrier pipe
Implementation Method 2
the at least one insulation layer being directly or indirectly bonded to at least the casing and the inner carrier pipe
Data Source
AI summary
This invention relates to a pipeline assembly especially for offshore installation comprising an inner carrier pipe, a casing and at least one closed-cell and/or solid thermal insulation material layer placed in between the casing and the inner carrier pipe, and the at least one insulation layer being directly or indirectly bonded to at least the casing and the inner carrier pipe. The pipeline assembly has improved bending properties which is achieved as the insulation material layer comprises at least one slit substantially transversely to the longitudinal direction of the pipeline assembly. The slit can be applied as a helical or circumferential cut, enabling the pipeline assembly to be rolled onto a reel or spool which greatly improves the pipeline assembly installation process. Methods of improving the bending properties of such a pipeline assembly are also described.