Pipe-in-Pipe Infill Structure for Insulation and Radial Strength
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Solution Overview
Problem
Current pipe-in-pipe (PiP) assemblies face challenges in achieving high-performance thermal insulation without compromising mechanical strength, and the manufacturing process is complex and labor-intensive due to the need for manual intervention and discontinuous processing.
Innovation Solution
A bundled infill structure is introduced, comprising a mixture of reinforcing and insulating elements, where the reinforcing elements provide mechanical resistance and the insulating elements offer superior thermal insulation, arranged in layers with angular staggering and tapered formations to optimize both properties, and auxiliary elements like heating wires and fibre-optic cables can be integrated within the structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional spacers and thermal insulation blankets are used in PiP assemblies, then thermal insulation performance is improved, but manufacturing complexity and labor intensity increase due to stepwise discontinuous processing
Solution Approach 1:
The patent combines spacers and thermal insulation blankets into a single integrated infill structure made of foam material. The foam simultaneously provides mechanical spacing between inner and outer pipes and thermal insulation, eliminating the need for separate components and stepwise assembly processes.
Solution Approach 2:
The infill structure uses foam material that combines the functions of spacers and thermal insulation in a single composite material. This foam can be injected to fill the annulus and cures to form a rigid structure that provides both mechanical support and thermal insulation properties.
2Adaptability or versatility
If spacers are installed on top of wires or fibre-optic cables, then cable accommodation is improved, but reliability deteriorates due to pinching of longitudinal elements during pipeline bending
Solution Approach 1:
The infill structure integrates cable accommodation into the foam material itself rather than using separate spacers placed on cables. The foam encases and protects cables while maintaining the annulus spacing, preventing pinching during pipeline bending.
Solution Approach 2:
The foam infill structure provides localized protection to cables at different positions within the annulus. The foam can be formulated with different densities or reinforcement in areas where cables are located, providing enhanced protection where needed while maintaining overall structural integrity.
3Ease of manufacture
If gaps between spacers and thermal insulation blankets are allowed, then manufacturing ease is improved, but thermal performance deteriorates due to significant thermal losses
Solution Approach 1:
The integrated foam infill structure eliminates gaps between spacers and insulation by combining both functions into a single continuous material that fills the entire annulus space, preventing thermal loss pathways.
Solution Approach 2:
The foam material can be injected in liquid form to fill all spaces and then cures to a rigid state, ensuring complete coverage without gaps. The curing process allows the material to expand and fill voids, ensuring continuous thermal insulation.
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
This approach enables the manufacture of PiP assemblies with enhanced mechanical strength and thermal insulation performance, allowing for a continuous automated manufacturing process using conventional winding machines, reducing thermal losses and improving reliability.
Implementation Method 1
the insulating elements provide greater thermal insulation than the reinforcing elements
Implementation Method 2
resistive electrical cables are disposed within the annulus between the inner and outer pipes, in thermal contact with the inner pipe
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
A pipe-in-pipe assembly comprises a bundled infill structure occupying an annulus between inner and outer pipes (12, 26) of the assembly. The infill structure is formed of a plurality of elongate elements laid along the inner pipe comprising a mixture of reinforcing elements (16B) and insulating elements (16A). The reinforcing elements have greater mechanical resistance than the insulating elements to radial compression whereas the insulating elements provide greater thermal insulation than the reinforcing elements. Pluralities of the reinforcing elements are positioned together within the infill structure to form reinforcing formations, such as spacer formations, embedded between insulating regions of the infill structure that are defined by pluralities of the insulating elements.