Cryostat arrangement
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Solution Overview
Problem
Cryogen-free superconducting magnet systems experience short 'time-to-quench' due to rapid heating when the cryocooler fails, and existing solutions that store small amounts of cryogen are not truly 'dry' or are limited in operating temperature windows.
Innovation Solution
Incorporating a heat sink device with magnetocaloric material that is thermally connected to the superconducting magnet arrangement, allowing ambient heat to flow and utilizing the magnetocaloric effect to absorb heat during cooler failures, thereby extending the 'time-to-quench' without the need for cryogenic fluids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a cryogen-free system is used with a cryocooler, then the system operates without cryogenic fluids, but the time-to-quench becomes very short when the cryocooler fails
Solution Approach 1:
The heat sink device is pre-cooled to cryogenic temperatures during normal operation using the cryocooler. When the cryocooler fails, this pre-cooled heat sink provides a reservoir of cold energy that delays the quench event, effectively performing the cooling function in advance before it is needed during a failure scenario.
Solution Approach 2:
The invention extracts the cryogenic cooling function from the active cryocooler system and stores it separately in the heat sink device. This separation allows the heat sink to independently provide thermal buffering during cryocooler failures, addressing the short time-to-quench problem without requiring continuous active cooling.
2Reliability
If small amounts of cryogen are stored in a reservoir to extend time-to-quench, then the cooling duration is increased, but the system is no longer truly cryogen-free
Solution Approach 1:
The invention replaces the chemical/phase-change-based cooling mechanism of cryogens with a solid-state heat sink device that operates on thermal energy storage principles. This substitution maintains the cryogen-free status while achieving extended time-to-quench through the heat sink's thermal mass and conductive coupling to the magnet coil.
3Reliability
If cryogen is used to extend time-to-quench, then the operating temperature window is limited to specific ranges, but the system loses adaptability to different temperature requirements
Solution Approach 1:
The heat sink device can be designed with different thermal masses, thermal conductivities, and heat capacity materials to adapt to various operating temperature requirements. By changing the physical parameters of the heat sink (material composition, geometry, thermal coupling), the system can be optimized for different temperature windows without being constrained by the fixed phase-change temperatures of specific cryogens.
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 effectively maintains the superconducting magnet at cryogenic temperatures for a significant duration even without active cooling, enhancing the 'time-to-quench' and maintaining the 'dry' operation of the cryostat arrangement.
Implementation Method 1
the heat sink device contains magnetocaloric material and that the heat sink device is thermally conductive with the superconducting magnet arrangement and/or with parts of the Cryostat assembly is connected, through which ambient heat can flow to the magnet assembly
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3b
AI summary
A cryostat arrangement which can be kept dry at a cryogenic operating temperature by means of a cryocooler (4), i.e. without the provision or supply of cryogenic fluids, wherein a superconducting magnet arrangement (1) and a heat sink device for extending the time until the superconducting magnet arrangement returns to the normally conducting state (="time-to-quench") if the active cooling fails, is characterized in that the heat sink device contains magnetocaloric material (3) and that the heat sink Device is thermally conductively connected to the superconducting magnet assembly and / or parts of the cryostat assembly, through which ambient heat can flow to the magnet assembly. In this way, the disadvantages of known generic arrangements can be avoided in a “dry” cryostat arrangement with simple technical means. In particular, the cryostat arrangement can really be operated “cryogen-free” and allows a sufficiently long “time to quench” in the event of any malfunctions.