Cryostat Precooling Using a Removable Thermal Short-Circuit Block
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Solution Overview
Problem
Cryostats with heat pipes require an excessively long precooling time to reach operating temperature, especially in the event of a cooling unit failure, which is inefficient and labor-intensive, and do not provide adequate protection against quenching of superconducting magnets.
Innovation Solution
A precisely fitting short circuit block with high thermal conductivity is inserted into the heat pipe during precooling, connected to a high-power cooling device, and later replaced by a two-stage cooler, allowing efficient heat transfer and reducing precooling time, while ensuring no air or moisture enters the cavity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a heat pipe is used for cooling the cryostat, then heat transfer efficiency is improved, but precooling time becomes excessively long
Solution Approach 1:
The patent applies preliminary action by introducing a short circuit block before the heat pipe is fully operational. This block provides a direct thermal conduction path from the cold head to the object to be cooled, enabling rapid precooling to reach the target temperature range where the heat pipe can then take over efficiently. The short circuit block is removed once the heat pipe becomes effective, having performed its preliminary cooling function.
2Reliability
If the cooling machine fails, then thermal bridge protection is needed, but the object to be cooled heats up quickly
Solution Approach 1:
The patent implements beforehand cushioning by providing a thermal insulation barrier between the object to be cooled and the external environment. This insulation cushioning reduces the rate of heat ingress in case of cooling machine failure, extending the time available for operator intervention or system recovery before quenching occurs.
3Speed
If a short circuit block is inserted for precooling, then precooling speed is improved, but device complexity increases
Solution Approach 1:
The patent applies the taking out principle by making the short circuit block a temporary, removable component. After serving its purpose during the precooling phase, the block is extracted from the system once the heat pipe becomes operational. This temporary extraction approach provides high precooling speed without permanently increasing device complexity.
4Loss of energy
If thermal contact surface is increased for better heat transfer, then heat transfer efficiency is improved, but risk of quenching increases
Solution Approach 1:
The patent applies dynamics by making the thermal contact configuration adjustable rather than fixed. The thermal contact surface area can be dynamically optimized based on operating conditions - providing sufficient contact for efficient heat removal during normal operation, while the system can adapt to reduce quenching risk under different thermal conditions through controlled adjustment of the thermal interface.
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 method significantly reduces precooling time and enhances the protection of superconducting magnets by allowing quick cooling and maintaining optimal heat transfer, thereby preventing quenching and extending the time to quench.
Implementation Method 1
A precisely fitting short circuit block with good thermal conductivity is inserted through the neck tube into the heat pipe, one free end of the short circuit block being thermally connected to a high-power cooling device, and its other end contacting the thermal contact surface
Implementation Method 2
a cryogenic working medium, which flows or drips through a heat pipe into an evaporator chamber during a condensation operation
Implementation Method 3
a cryogenic working medium, which flows or drips through a heat pipe into an evaporator chamber during a condensation operation
Implementation Method 4
one free end of the short circuit block being thermally connected to a high-power cooling device
Data Source
AI summary
A method is provided for precooling a cryostat having a hollow cold head turret into which a neck tube protrudes and connects an object to be cooled to the exterior of the cryostat, wherein a cold head having a cold head stage for cooling a cryogenic working medium may be introduced into the neck tube. During a condensation operation the cryogenic working medium flows through a heat pipe into an evaporator chamber which is thermally conductively connected to the object to be cooled. During a precooling phase a precisely fitting, thermally conductive short circuit block is inserted through the neck tube into the heat pipe to provide thermal conduction between the object to be cooled and a cooling device The short circuit block is removed from the heat pipe after the target temperature is reached, and heat is subsequently transmitted through the heat pipe during a condensation operation.