Superfluid Helium Thermal Switch for Low-Maintenance DNP Cooling
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Solution Overview
Problem
Existing dynamic nuclear polarization (DNP) systems face challenges with lengthy maintenance times and complex mechanical configurations in their cooling systems, which hinder efficient servicing and temperature control.
Innovation Solution
A cooling system utilizing a liquid thermal switch formed by superfluid helium between contact surfaces, eliminating mechanical components and ensuring perfect thermal contact without mechanical means, thereby compensating for surface irregularities and providing infinite thermal conductivity below 2.5 Kelvin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional mechanical thermal switches are used in the cooling system, then thermal contact can be maintained, but maintenance time increases and system complexity increases
Solution Approach 1:
The patent replaces mechanical thermal switch components with a liquid thermal switch comprising liquid metal or liquid alloy. This substitution eliminates mechanical contact surfaces that require maintenance while maintaining effective thermal coupling between the cryogenic chamber and sample holder through fluid thermal conduction.
Solution Approach 2:
The patent utilizes liquid metal or liquid alloy as a fluid thermal conductor to transfer heat between the cryogenic chamber and sample holder. The liquid thermal switch leverages hydraulic principles by using fluid circulation and phase change properties to maintain thermal contact without mechanical components.
2Reliability
If mechanical thermal switches are used, then thermal contact can be established, but device complexity increases
Solution Approach 1:
The patent eliminates mechanical thermal switch components by implementing a liquid thermal switch system. The liquid metal or liquid alloy provides thermal conduction through fluid circulation, removing the need for mechanical contact surfaces, actuators, and associated control mechanisms, thereby simplifying the overall device architecture.
Solution Approach 2:
The patent changes the physical state of the thermal conductor from solid mechanical components to liquid metal or liquid alloy. This parameter change allows the thermal switch to adapt to surface irregularities and maintain thermal contact through fluid properties rather than rigid mechanical structures, reducing system complexity.
3Temperature
If conventional cooling systems are used, then samples can be cooled to low temperatures, but maintenance frequency increases
Solution Approach 1:
The patent replaces mechanical cooling system components with a liquid thermal switch system that uses liquid metal or liquid alloy. This substitution reduces maintenance frequency by eliminating mechanical wear and tear, as the liquid thermal switch requires no moving parts or mechanical adjustments to maintain thermal contact during cryogenic cooling operations.
Solution Approach 2:
The liquid thermal switch system provides self-maintaining thermal contact through its fluid properties. The liquid metal or liquid alloy automatically adapts to surface irregularities and maintains thermal coupling without requiring manual intervention or mechanical adjustments, extending the maintenance interval of the cooling system.
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 system reduces maintenance downtime from days to hours, allows for rapid de-icing procedures, and maintains consistent temperature control, enhancing the efficiency and reliability of DNP operations.
Implementation Method 1
the liquid thermal switch includes superfluid helium
Implementation Method 2
after helium becomes superfluid helium at a temperature of approximately 1 Kelvin
Implementation Method 3
monitoring, via the processor, pressure as the gaseous helium flows into the interspatial space and cools down with the pressure lowering
Data Source
AI summary
A cooling system associated with a dynamic nuclear polarization system includes a cryogenic chamber including a cryogenic fluid. The cooling system also includes a pot positioned within the cryogenic chamber, the pot being at least partially surrounded by the cryogenic fluid. The cooling system further includes a removable sample sleeve inserted into the pot so that a lower portion of the removable sample sleeve is positioned in the pot and an upper portion of the removable sample sleeve protrudes out of the pot. The cooling system even further includes a liquid thermal switch configured to be disposed between and directly contact an inner surface of a bottom of the pot and a bottom surface of the lower portion of the removable sample sleeve, wherein the liquid thermal switch includes superfluid helium.