Outer Tube Support Sections for Double-Walled Pipe Wear Reduction
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Solution Overview
Problem
In double-walled pipe arrangements exposed to high thermal loads, mechanical vibrations cause wear at the second end section of the outer tube and spacers due to axial relative movement between the inner and outer tubes, which is not effectively addressed in existing designs, especially in gas turbines where the outer tube is not connected to the inner pipe at its second end section.
Innovation Solution
The outer tube features radially inwardly projecting support sections on its second end section, which are in contact with the spacer, allowing for radial stabilization while maintaining axial movement, reducing wear by distributing contact over a small area or points, and can be produced by deforming the outer tube to form convex or spherical cap-like sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the outer tube is not connected to the inner pipe at its second end section, then thermal expansion compensation is enabled, but mechanical vibrations cause the outer tube to hit or rub against the spacer or inner tube leading to high wear
Solution Approach 1:
The second end section of the outer tube is segmented into multiple radially inwardly projecting support sections distributed circumferentially. These support sections are formed by deforming the outer tube material inward, creating discrete contact points with the spacer that provide stability while allowing axial movement for thermal expansion compensation.
Solution Approach 2:
The outer tube has different structural qualities at different locations: the first end section is materially connected to the spacer for stability, while the second end section has localized radially inwardly projecting support sections that provide point contact stability without full circumferential connection, enabling both wear reduction and thermal expansion compensation.
2Stability of the object's composition
If the outer tube is materially connected to the spacer at both ends, then stability is improved, but thermal expansion compensation is restricted
Solution Approach 1:
The connection at the second end section is segmented into discrete radially inwardly projecting support sections rather than a continuous material connection. This segmentation provides radial stability through point contacts while leaving gaps that allow axial movement for thermal expansion compensation.
Solution Approach 2:
Instead of connecting the outer tube to the spacer through material bonding at the second end section, the invention inverts the approach by creating radially inwardly projecting support sections that contact the spacer externally, providing stability without restricting axial movement.
3Reliability
If a closure with locking ring and inner ring is used, then airtight seal is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The invention merges the support function and sealing function into a single integrated structure. The radially inwardly projecting support sections at the second end section simultaneously provide radial stability and contribute to sealing, eliminating the need for separate locking rings and inner rings required in conventional closures.
Solution Approach 2:
The support sections serve multiple functions: they provide radial stability by contacting the spacer, enable sealing by maintaining proper spacing between tubes, and allow axial movement for thermal expansion. This multi-functionality reduces the overall component count and manufacturing complexity.
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 design prevents striking movements caused by vibrations, reducing wear on the outer tube and spacers, and allows for stable mounting of the outer pipe on the inner pipe, enabling efficient thermal expansion compensation.
Implementation Method 1
The support sections bear against the spacer over a small area or even at certain points. As a result, the outer tube is stabilized in the radial direction relative to the inner tube, but the relative movement of the inner tube and the outer tube in the axial direction is still possible.
Implementation Method 2
In the case of double-walled pipe arrangements that are exposed to high thermal loads, there is the problem that an outer pipe, which serves as heat protection, and an inner pipe, which, for example, conducts a hot fluid, such as coolant or oil, must be able to move relative to one another in order to accommodate different thermal expansions to be able to compensate.
Implementation Method 3
The support sections bear against the spacer over a small area or even at certain points. As a result, the outer tube is stabilized in the radial direction relative to the inner tube, but the relative movement of the inner tube and the outer tube in the axial direction is still possible. Vibrations that act on the pipe arrangement thus no longer lead to striking movements of the second end section of the outer pipe, so that rapid wear can be counteracted.
Data Source
Figure 1~2
AI summary
The invention relates to a pipe arrangement (10) with a fluid-carrying inner pipe (12) and an outer pipe (14) surrounding the inner pipe (12), wherein spacers (20, 24) are arranged between the inner pipe (12) and the outer pipe (14) such that a space (16) is formed between the inner pipe (12) and the outer pipe (24), wherein the outer pipe (14) is materially connected at its first axial end section (18) to a first spacer (20), which is materially connected to the inner pipe (12), and wherein the outer pipe (14) is arranged at its second axial end section (22) at least partially at a radial distance (26) to a second spacer (24), which is materially connected to the inner pipe (12).According to the invention, it is proposed that the outer tube (14) has several circumferentially distributed, radially inwardly projecting support sections (28) at its second end section (22), which are in contact with the second spacer (24).