Superconductive Cable End Termination Rupture Discs
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Solution Overview
Problem
Superconductive cables face the risk of inner container bursting due to sudden pressure increases from electrical breakdowns or short circuits, which cannot be dissipated quickly, posing a threat to the vacuum insulation and overall end termination structure.
Innovation Solution
The end termination design incorporates a first rupture disc that opens at maximum permissible pressure to release contents into a bursting space with super insulation, and a second rupture disc that opens at a lower pressure to further alleviate pressure, ensuring the inner container and vacuum insulation are protected from damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the inner container is made pressure-resistant to withstand sudden pressure increases, then the container can prevent bursting, but the container cannot be made infinitely strong and may still burst under extreme conditions
Solution Approach 1:
The first rupture disc is pre-installed in the inner container wall to open at a predetermined pressure threshold, and the second rupture disc is pre-installed in the outer container wall to open at a lower predetermined pressure threshold. These preliminary protective measures ensure that when sudden pressure increases occur, the rupture discs will automatically activate to release pressure before the container can burst, thus protecting the vacuum insulation and preventing catastrophic failure.
2Reliability
If rupture discs are installed to release pressure, then the risk of container bursting is reduced, but the vacuum insulation between inner and outer containers is exposed to pressure damage
Solution Approach 1:
The pressure relief function is distributed across two different spatial dimensions: the first rupture disc is positioned in the inner container wall while the second rupture disc is positioned in the outer container wall. This spatial distribution ensures that when the first rupture disc opens, pressure is released into the annular space, and when the second rupture disc opens, pressure is released to the external environment, thereby protecting the vacuum insulation in the annular space from pressure damage throughout the entire process.
3Device complexity
If a single rupture disc is used to release pressure, then the structure is simple, but the vacuum insulation cannot be adequately protected from pressure increases
Solution Approach 1:
The pressure relief function is segmented into two distinct rupture discs positioned at different locations and operating at different pressure thresholds. The first rupture disc is segmented from the second rupture disc, with each serving a specific protective function. This segmentation allows the system to protect the vacuum insulation more effectively than a single rupture disc could achieve alone.
4Reliability
If the first rupture disc opens at maximum permissible pressure, then pressure is released to prevent bursting, but the pressure increase may already have damaged the vacuum insulation
Solution Approach 1:
The second rupture disc is designed to open at a pressure threshold lower than that of the first rupture disc, creating a preliminary protective action. When pressure increases begin to affect the system, the second rupture disc opens first to release pressure into the annular space, preventing pressure from reaching levels that would damage the vacuum insulation. This preliminary anti-action occurs before the first rupture disc opens at the maximum permissible pressure.
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 effectively prevents further damage to the inner container and end closure by allowing controlled release of coolant, thereby preventing bursting and safeguarding the vacuum insulation from pressure-induced damage.
Implementation Method 1
If the pressure in the inner container suddenly rises above the permitted maximum pressure and thus above the response pressure of the first bursting disc
Implementation Method 2
the second rupture disc, on which no internal pressure is exerted during undisturbed operation, is designed in such a way that it already opens at a pressure which is considerably lower than the pressure required to open the first rupture disc
Implementation Method 3
The delimited, evacuated bursting space is fitted with super insulation on its outside, so that there is no such temperature gradient between the inside and outside of the first bursting plate that could lead to an increased incidence of heat in the inner container
Implementation Method 4
a metallic outer container, which is separated from the inner container by a space in which vacuum insulation is attached
Data Source
AI summary
An end termination for a superconducting cable (1) is described, consisting of a pressure-resistant metallic inner container (2) containing a liquid coolant and into which the cable projects, and a metallic outer container (3) separated from the inner container (2) by an intermediate space (4) containing vacuum insulation. To protect the end termination against external forces, a first rupture disc (6) is installed in the wall of the inner container (2), and a second rupture disc (7) is installed in the wall of the outer container (3) at the level of the first rupture disc (6). Between the two rupture discs (6, 7), an evacuated rupture space (8) is provided, which contains superinsulation and is sealed off from the intermediate space (4) containing the vacuum insulation by a pressure-resistant wall (9).