Cryogenic Pipe Insulation Composite Structure
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Solution Overview
Problem
Current marine pipelines for cryogenic applications face challenges with thermal expansion and insulation, leading to high material and construction costs due to the use of nickel-based alloys like INVAR, which are expensive and inefficient in managing thermal stresses.
Innovation Solution
A pipe design featuring a tubular body with reinforcing layers, an axial strengthening means such as a braid, and an insulation layer, specifically suited for cryogenic temperatures, to manage thermal expansion and provide effective insulation while reducing material costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nickel-based alloys like INVAR are used to manage thermal expansion, then thermal stress control is improved, but material cost increases significantly
Solution Approach 1:
The patent employs a composite structure consisting of an inner pipe made of austenitic stainless steel (316L) and an outer pipe made of carbon steel (X65), with insulation material filling the annular space between them. This composite construction allows each material to perform its optimal function: the austenitic inner pipe resists thermal contraction at cryogenic temperatures, while the carbon steel outer pipe provides structural strength and cost-effectiveness. The insulation layer further manages thermal expansion differentials, eliminating the need for expensive nickel-based INVAR alloys while maintaining reliable thermal stress control.
2Reliability
If conventional insulation methods are used, then insulation effectiveness is insufficient, but adding thicker insulation increases device complexity
Solution Approach 1:
The patent implements a nested pipe configuration where the inner austenitic stainless steel pipe is placed inside an outer carbon steel pipe, with insulation material filling the annular space between them. This nested structure provides effective thermal insulation without requiring excessive thickness, as the concentric arrangement maximizes insulation efficiency within a compact radial envelope. The insulation layer is contained within the annular space, avoiding external protrusions and simplifying overall structural complexity.
3Reliability
If pipe-in-pipe systems with vacuum insulation are used, then insulation performance is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent specifies that the insulation material filling the annular space between the inner and outer pipes should have a cellular or porous structure. This porous insulation material provides effective thermal resistance through trapped air pockets and reduced thermal conduction pathways, achieving high insulation performance without requiring vacuum conditions. The porous structure is easier to manufacture than vacuum insulation, as it can be directly placed or injected into the annular space during the pipe fabrication process, significantly reducing manufacturing complexity while maintaining superior insulation performance.
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 pipe effectively transports cryogenic fluids with reduced thermal stresses and improved insulation, offering robustness and temperature resistance at a lower cost compared to previous solutions.
Implementation Method 1
an insulation layer, specifically suited for cryogenic temperatures, to manage thermal expansion and provide effective insulation
Data Source
Figure 1~2
Figure 3
AI summary
A pipe (100) comprising an outer rigid conduit (30) and an inner tubular structure, the inner tubular structure comprising a flexible hose (10), wherein the hose comprises a tubular body disposed between inner and outer gripping members, the tubular body including a sealing layer, and being formed of a material capable of withstanding cryogenic temperatures, wherein the inner tubular structure has insulation properties sufficient to protect the outer conduit from the low temperature of cryogenic fluid flowing within the inner tubular structure.