Vacuum-Insulated Johnston Coupling With Galvanic Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current plug-in couplings for cryogenic lines lack effective galvanic isolation and thermal insulation, leading to energy losses and increased fire hazards during the transportation of cryogenic media, especially when handling extremely cold liquids like LNG, hydrogen, and helium.
Innovation Solution
A plug-in coupling design featuring a coupling plug and socket with an electrically insulating seal, an insulating sleeve, and an insulating disk between connecting flanges, ensuring galvanic isolation and enhanced thermal insulation through vacuum insulation, along with additional seals in the warm area to prevent medium evaporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If uninsulated pipes and couplings are used for transporting cryogenic liquids, then the device complexity is reduced, but thermal insulation performance deteriorates leading to energy losses and evaporation
Solution Approach 1:
The coupling consists of an inner double-walled pipe nested within an outer double-walled pipe, creating a pipe-in-pipe structure. The inner pipe carries the cryogenic medium while the outer pipe provides additional insulation and structural support. This nested configuration maintains excellent thermal insulation without requiring complex external insulation layers or additional components.
2Reliability
If galvanic isolation is implemented in cryogenic couplings, then electrical safety is improved, but device complexity increases due to additional insulating components
Solution Approach 1:
An electrically insulating seal is introduced as an intermediary component between the inner and outer pipes at the distal end of the coupling. This seal serves dual purposes: it provides galvanic isolation to prevent electrical hazards while simultaneously maintaining the vacuum seal for thermal insulation. The insulating sleeve and insulating disk further act as intermediary elements that bridge the connection flanges while ensuring electrical isolation, thus achieving safety without proportionally increasing complexity.
3Loss of energy
If vacuum insulation is used in double-walled pipes, then thermal insulation performance is improved, but manufacturing complexity increases
Solution Approach 1:
The vacuum insulation system is segmented into modular components: the inner double-walled pipe, the outer double-walled pipe, and the coupling sections. Each segment can be manufactured and evacuated separately, then assembled together. This segmentation allows for standardized production of pipe sections that can be joined using the specialized coupling, reducing overall manufacturing complexity compared to producing long continuous vacuum-insulated pipes.
4Loss of energy
If longer pipe-in-pipe coupling lengths are used, then thermal insulation performance is improved, but the length of the coupling increases
Solution Approach 1:
The coupling employs composite construction with inner and outer double-walled pipes made of materials optimized for different functions. The inner pipe uses materials with low thermal conductivity for the medium-carrying section, while the outer pipe provides structural strength and additional insulation. This composite approach allows for effective thermal insulation over shorter lengths compared to single-material constructions, reducing the overall coupling length while maintaining insulation performance.
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
The solution reduces energy losses and minimizes the risk of fire hazards by maintaining thermal insulation and ensuring electrical separation, effectively handling cryogenic media transport while preventing medium evaporation and potential explosions.
Implementation Method 1
Simply put, a Johnston coupling consists of two double-walled, vacuum-insulated pipes inserted into one another
Implementation Method 2
The quick-connect coupling according to the invention is characterized in that the seal at the distal end of the coupling plug is electrically insulating
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A quick-connect coupling is proposed for connecting a first and a second double-walled vacuum-insulated cryogenic conduit. The coupling comprises a plug and a socket. The plug has an inner and an outer tube section, as well as a first connection flange, and is connected to the first cryogenic conduit. The socket has an inner and an outer tube section, as well as a second connection flange, and is connected to the second cryogenic conduit. An annular seal is arranged at a distal end of the plug, creating a sealed connection between the socket and the plug when the plug is fully inserted into the socket.The plug-in coupling is characterized by the fact that (a) the seal at the distal end of the plug is electrically insulating, (b) an insulating sleeve is arranged on the outer tube section of the plug, and (c) an insulating washer is located between the first and second connection flanges when the plug is inserted into the socket. The plug-in coupling provides galvanic isolation between the plug and the socket.