Flexible quick-connect heat transfer coupling for cryocoolers
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Solution Overview
Problem
Existing cryocooler installations face challenges in achieving efficient mechanical and thermal connections, particularly in conduction-cooled devices like superconducting magnets, where limited accessibility and varying component sizes complicate the process of heat extraction at low temperatures.
Innovation Solution
The design of a cryohead heat transfer coupling featuring an annulus with a flexible link module and thermally conductive blocks, where the materials' differential thermal expansion allows for a 'shrink-fitting' mechanism that ensures intimate contact and efficient heat conduction without the need for bolts or screws, accommodating size changes during cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional bolted or clamped couplings are used to connect cryocooler stages to target components, then mechanical connection strength is improved, but installation complexity and time increase due to limited accessibility in vacuum chambers
Solution Approach 1:
The coupling is divided into two separate parts: a socket portion that attaches to the cryocooler stage and a post portion that attaches to the target component. This segmentation allows each part to be independently installed - the post can be attached to the target component first, then the socket is simply inserted over it, eliminating the need for complex bolting or clamping operations in hard-to-reach vacuum chamber locations.
Solution Approach 2:
The socket portion is designed to fit over the post portion, creating a nested configuration where one component contains another. This nesting approach simplifies installation by allowing the socket to be slipped over the post in a single motion, providing secure mechanical connection without requiring fasteners that would be difficult to access and tighten in confined vacuum chamber spaces.
2Reliability
If rigid couplings are used to maintain precise thermal contact, then heat conduction efficiency is improved, but adaptability to component size variations and thermal contraction is worsened
Solution Approach 1:
The coupling incorporates flexible elements that allow dynamic adjustment to accommodate thermal contraction and component size variations. The flexible link or bellows structure can compress or expand as components contract at cryogenic temperatures, maintaining continuous thermal contact and heat conduction efficiency without requiring precise pre-adjustment for thermal effects.
Solution Approach 2:
The coupling design accounts for parameter changes by allowing the physical dimensions and flexibility characteristics to adapt with temperature. The flexible portion changes its mechanical properties with temperature, becoming more compliant at cryogenic temperatures to maintain contact pressure and thermal connection as components contract, thereby preserving heat conduction efficiency despite dimensional changes.
3Reliability
If multiple fastening elements (bolts, screws, clamps) are used to secure couplings, then connection reliability is improved, but device complexity and installation time increase
Solution Approach 1:
By segmenting the coupling into socket and post portions, the design eliminates the need for multiple fastening elements. The simple insert-over configuration provides reliable connection through the interference fit and geometric constraints of the nested geometry, reducing the coupling mechanism to its essential function without complex fastening hardware.
Solution Approach 2:
The design replaces the traditional mechanical fastening system (bolts, screws, clamps requiring tools and multiple steps) with a simpler insert-over mechanism that relies on geometric interference and flexible material compliance. This substitution maintains connection reliability through the physical interlocking and material flexibility while dramatically simplifying the coupling structure and installation process.
4Manufacturing precision
If precision alignment features are added to ensure proper coupling alignment, then thermal contact quality is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The flexible portion of the coupling provides dynamic alignment tolerance, allowing the socket to self-align with the post during insertion. The flexibility absorbs minor misalignments that would otherwise require precision machining of alignment features, achieving proper thermal contact through material compliance rather than geometric precision.
Solution Approach 2:
The coupling leverages parameter changes in the flexible material to accommodate alignment variations. As the flexible link or bellows compresses during insertion, it naturally guides the components into proper alignment, eliminating the need for precision-machined alignment features while maintaining thermal contact quality through the compliant material's ability to conform to the mating surfaces.
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 solution enables efficient heat extraction and maintenance by ensuring a stable, compressive thermal connection that maintains performance across varying temperatures, simplifying installation and removal within vacuum chambers, and allowing for effective cooling of superconducting magnets.
Implementation Method 1
the socket parts, that are made from materials that as a whole contract more than the materials of the post, contract and compress over the post parts and produce mechanical-thermal connection desired for good conduction cooling
Implementation Method 2
heat removal by the cryohead is achieved inside a vacuum chamber, commonly called a cryostat, through conduction by means of physical contacts with the target components
Data Source
AI summary
Embodiments for a cryohead heat transfer coupling as well as methods for extracting heat from an article using these couplings are provided. Couplings employ a component made from a material having a greater mean thermal coefficient of expansion than the mean thermal coefficient of other coupling components and of the article. As a result, differential contraction during cryocooling contributes a shrink fitting of a portion of the coupling resulting in enhanced thermal conduction when cooling and a releasing of the coupling when ambient temperature is restored.