Vacuum-Insulated Pipe Sealing for Thermal Expansion Relief
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Solution Overview
Problem
Existing vacuum heat-insulating vessel structures face challenges when operating at high temperatures due to thermal expansion, leading to dimensional differences between inner and outer tubes, which can cause distortion and disjoin the welded parts, and existing seal members either lack high-temperature resistance or elasticity, making them unsuitable for absorbing these differences.
Innovation Solution
A decompression heat-insulating pipe structure with a shifting mechanism that allows the outer and inner tubes to move relative to each other, positioning the seal member to absorb thermal expansion while maintaining a decompressed space, enabling the use of low-elasticity, high-temperature-resistant seal members by shifting the tubes to cancel and reapply pressure on the seal members as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If welding is used to join inner tube and outer tube, then integrated structure is achieved, but distortion stress causes welded part disjoining at high temperatures
Solution Approach 1:
The structure is divided into separate inner tube and outer tube components that are not rigidly joined. The inner tube can expand independently within the outer tube, with the seal member allowing relative movement between the two segments to accommodate thermal expansion differences.
Solution Approach 2:
The seal member's physical parameters (elasticity, compression tolerance) are optimized to allow the inner tube to expand radially and axially at high temperatures while maintaining the seal. The seal member can be compressed within a specific range to absorb dimensional changes.
2Reliability
If elastic seal member is used to absorb dimensional difference, then sealing is maintained, but heat resistance is insufficient at temperatures above 300°C
Solution Approach 1:
The seal member is constructed from composite materials or treated materials that combine heat resistance with elastic properties. This allows the seal member to maintain its sealing function through elastic deformation even at temperatures where conventional elastomers would degrade.
Solution Approach 2:
The seal member is designed to dynamically adapt to dimensional changes in the inner tube through elastic deformation. It can be compressed and expanded as the inner tube thermally expands and contracts, maintaining the seal throughout the temperature cycle.
3Temperature
If high heat resistance seal member is used, then thermal stability is improved, but elasticity is reduced and cannot absorb dimensional difference
Solution Approach 1:
The seal member uses composite materials or specially treated materials that simultaneously provide high heat resistance and retained elasticity. This breaks the conventional trade-off between thermal stability and elastic adaptability.
Solution Approach 2:
The seal member is pre-compressed within a specific range during assembly to create a cushioning effect that allows it to absorb subsequent thermal expansion of the inner tube. This pre-compression enables the heat-resistant material to still provide elastic accommodation of dimensional changes.
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 configuration suppresses distortion due to thermal expansion, allows the use of seal members with low elasticity and high heat resistance, and maintains high heat insulation performance, enabling the structure to operate effectively at high temperatures without thermal degradation.
Implementation Method 1
using a bellows for elastic deformation to absorb dimensional differences
Implementation Method 2
the inner tube is expanded in diameter because of thermal expansion by heating
Implementation Method 3
the seal member being configured to keep the space between the outer tube and the inner tube in a decompression state
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
Provided is a decompression heat-insulating pipe structure (1) that can be used in the system operating at high temperatures. A decompression heat-insulating pipe structure of the present disclosure includes: an outer tube (10) and an inner tube (20) each having a flange (11; 12; 21; 22); and a seal member (30) between the flanges, the seal member being configured to keep a space between the outer tube and the inner tube in a decompression state, and a shifting means (40) configured to shift the outer tube and the inner tube relatively so as to selectively dispose the tubes at a pressing position to press the seal member between the flanges and at a cancellation position to cancel the pressing of the seal member.