Vacuum-Insulated Double-Wall Piping for Cryogenic Load Relief
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Solution Overview
Problem
Vacuum-insulated double-wall piping for cryogenic fluids faces issues with stress generation and potential damage at connection points due to internal-pressure loads, as the bellows provided for contraction differences cannot handle these loads effectively.
Innovation Solution
The solution involves providing protruding and receiving parts on the inner and outer pipes, respectively, with heat-insulating members, configured to move and thread securely, allowing the internal-pressure load to be received as a tensile load, thereby reducing moments on connection parts and preventing stress-related damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a bellows is provided to the inner pipe to accommodate contraction difference between inner and outer pipes, then the contraction difference is ameliorated, but the bellows cannot withstand internal-pressure loads, causing high stress at connection parts
Solution Approach 1:
A load-bearing rod is introduced as an intermediary element between the inner pipe and outer pipe. This rod transfers the internal-pressure load from the inner pipe to the outer pipe, preventing the load from acting directly on the bellows and connection parts. The load-bearing rod serves as a mediator that separates the contraction accommodation function (bellows) from the load-bearing function (rod), resolving the contradiction between accommodating contraction and withstanding pressure loads.
Solution Approach 2:
The system is segmented into distinct functional components: the bellows handles only the contraction difference between inner and outer pipes, while the load-bearing rod handles the internal-pressure load. This segmentation allows each component to be optimized for its specific function, preventing the bellows from being subjected to pressure loads it cannot withstand.
2Quantity of substance
If the inner pipe is subjected to cryogenic fluid, then the cryogenic fluid can be transported, but the inner pipe contracts to ultra-low temperatures while the outer pipe remains at normal temperature, creating contraction difference
Solution Approach 1:
The invention explicitly accounts for and compensates for thermal contraction of the inner pipe when subjected to cryogenic temperatures. The bellows component is specifically designed to accommodate the contraction difference that occurs between the cold inner pipe and the warmer outer pipe, allowing the system to maintain structural integrity despite the temperature differential required for cryogenic fluid transport.
3Loss of energy
If protruding and receiving parts are provided with heat-insulating members, then heat insulation is maintained at contact points, but the structure becomes more complex
Solution Approach 1:
Heat-insulating members are applied locally only at the protruding and receiving parts where contact occurs between inner and outer pipes. This localized approach provides heat insulation precisely where needed to prevent thermal bridges, without insulating the entire pipe structure. The solution balances heat loss prevention with structural simplicity by applying insulation only at critical contact points.
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 significantly reduces the moment acting on connection parts between the inner and outer pipes, preventing damage and maintaining effective heat insulation to prevent cryogenic fluid evaporation or liquefaction near the outer surface.
Implementation Method 1
an outer pipe 2 that is provided to the outer periphery of the inner pipe 1 with a vacuum layer 3 interposed therebetween
Implementation Method 2
contact surfaces of at least the protruding parts 7 or the receiving parts 8 furthermore being configured from heat-insulating members 9
Data Source
AI summary
Vacuum-insulated double-wall piping for transporting a cryogenic fluid includes an inner pipe that includes a bellows part, and an outer pipe that is provided to the outer periphery of the inner pipe with a vacuum layer interposed therebetween, the vacuum-insulated double-wall piping having a straight pipe section and elbow sections. The vacuum-insulated double-wall piping is characterized in that the bellows part is provided to an inner-pipe straight pipe section positioned in the straight pipe section, protruding parts that protrude outward toward the outer pipe are provided to inner-pipe elbow sections positioned in the elbow sections, and receiving parts that come into contact with the protruding parts are provided to outer-pipe elbow sections positioned in the elbow sections, contact surfaces of at least the protruding parts or the receiving parts furthermore being configured from heat-insulating members.