Dual-Layer Shrink Sleeve for Insulated Pipe Sealing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for joining insulated pipes in district heating/cooling systems face difficulties in sealing wall holes due to the high temperature resistivity of cross-linked polymer-based materials, making welding processes challenging and costly, and the use of protective metal discs is time-consuming and inefficient.
Innovation Solution
A shrink sleeve made of a combination of two polymer-based materials, where one is susceptible to irradiation and the other is resistant and weldable, allowing for uniform irradiation without adding parts, enabling effective sealing and longitudinal extension of pipelines without compromising the tubular shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the sleeve material is fully cross-linked to achieve high mechanical strength and temperature resistivity, then the structural integrity and shrinkage performance are improved, but the weldability of the material deteriorates making it impossible to seal wall holes
Solution Approach 1:
The patent applies local quality by creating a multi-layer structure where the first layer (facing the wall hole) is made of polymer material that is less cross-linked to maintain weldability, while the second layer is fully cross-linked to provide mechanical strength and shrinkage performance. This allows different regions of the sleeve to have different cross-linking degrees tailored to their specific functional requirements.
Solution Approach 2:
The patent uses composite materials by combining two different polymer materials with different cross-linking properties in a single sleeve structure. The first material is designed to be weldable with lower cross-linking, while the second material provides high strength with full cross-linking. This composite approach resolves the contradiction between strength and weldability by integrating materials with complementary properties.
2Ease of manufacture
If protective metal discs are mounted on the wall material to prevent full cross-linking and enable welding, then the weldability is improved, but the manufacturing process becomes time-consuming and costly
Solution Approach 1:
The patent extracts the need for protective metal discs by designing a multi-layer sleeve structure where the first layer is inherently weldable due to its lower cross-linking degree. This eliminates the requirement for additional protective components and their associated mounting operations, streamlining the manufacturing process.
Solution Approach 2:
The patent merges the protective function and the structural function into a single integrated sleeve component. The first layer of the sleeve itself provides the weldable surface, combining what were previously separate functions (protective disc and sleeve structure) into one unified component, thereby improving manufacturing efficiency.
3Strength
If the sleeve diameter is extended after irradiation to achieve proper fit, then the shrinkage fastening effect is improved, but the wall holes become difficult to access for welding operations
Solution Approach 1:
The patent segments the sleeve into two functional layers: the first layer optimized for weldability with lower cross-linking, and the second layer optimized for shrinkage fastening with full cross-linking. This segmentation allows the welding operations to be performed on the first layer before or during the shrinkage process, while the second layer provides the necessary fastening effect.
Solution Approach 2:
The patent applies preliminary action by ensuring the first layer is designed to be weldable before the shrinkage process. The weldable surface is prepared in advance through controlled cross-linking, allowing welding operations to be performed prior to or during the diameter extension and shrinkage process, avoiding accessibility issues.
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 solution allows for efficient sealing of wall holes with improved weldability and reduced manufacturing costs, ensuring high-quality integration and uniform insulation without the need for additional components or complex processes.
Implementation Method 1
the sleeve is normally made of a polymer-based material, which after manufacturing is exposed to irradiation such as an e-beam (electron beam). After such a treatment for example polyethylene is denoted PEX or PE-Xc. The sleeve is hereby cross-linked
Implementation Method 2
The sleeve is hereby cross-linked, meaning that the polymer fibers of the material will change direction and link to other layers (molecule chains)
Implementation Method 3
After irradiation, the ends of the sleeve are heated and the diameter of these is extended... As described, the sleeve is fastened to the casing of the two insulated pipes by heating the ends, whereby the material here will try to reach its initial size. Hence, the material in the ends shrinks as a result of the heating thereof
Data Source
Figure 1a~2b
Figure 3a~5b
Figure 6~8
AI summary
This invention relates to a shrink sleeve (300) for joining the casing of two insulated pipes lying end-to-end, where the shrink sleeve (300) has a tubular shape comprising a first polymer-based material (320) susceptible to irradiation. The tubular shape of the shrink sleeve (300) consists of the first polymer-based material (320) and a second polymer-based material (322), where the second polymer-based material (322) is resistant to the irradiation. Further, the second polymer-based material (322) can be weldable.