Cryocooler

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Solution Overview

Problem

Multistage cryocoolers face challenges in maintaining high cooling performance due to susceptibility to radiant heat, particularly from the insertion holes of temperature sensors, which directly radiate heat to the cooling stages, reducing their effectiveness.

Innovation Solution

The cryocooler design incorporates a radiation shield that accommodates the second cooling stage and includes a strategically positioned cable insertion hole in the radiation shield, preventing direct radiation of heat to the cooling stage, and optionally uses a shielding member to block radiant heat paths, ensuring efficient heat reflection and maintaining low temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a temperature sensor is installed on the second cooling stage to detect temperature, then temperature monitoring capability is improved, but radiant heat from the insertion hole directly reaches the cooling stage, reducing cooling performance

Engineering Contradiction:

Improvetemperature detection capabilityVSAvoidradiant heat reaching cooling stage

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

A shielding member is introduced as an intermediary element between the insertion hole and the second cooling stage. This shielding member blocks the direct path of radiant heat while allowing the temperature sensor to function, thus mediating between the need for temperature monitoring and the need to prevent heat radiation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The radiation shield is designed with a specific local structure at the insertion hole area, where the shielding member is positioned to block radiant heat only in the critical path toward the cooling stage, while maintaining other necessary functions of the radiation shield in different areas.

Inventive Principle:

Principle #3Local quality

2Temperature

If a radiation shield is used to block radiant heat from the second cooling stage, then cooling performance is improved, but the insertion hole for temperature sensor cable creates a direct path for radiant heat entry

Engineering Contradiction:

Improvecooling temperature maintenanceVSAvoidradiation shield structure with insertion hole

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The shielding member acts as an intermediary within the radiation shield structure, filling the functional gap created by the insertion hole. It restores the heat-blocking capability in the specific region where the insertion hole compromises the overall radiation shield effectiveness.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Temperature

If multistage cryocooler design is implemented to achieve lower temperatures, then cooling capability is improved, but susceptibility to radiant heat increases

Engineering Contradiction:

Improvecryogenic temperature achievementVSAvoidradiant heat susceptibility

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

The shielding member serves as a localized intermediary protection mechanism within the multistage cryocooler system, specifically addressing the radiant heat susceptibility of the second cooling stage without interfering with the overall multistage cooling architecture.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 configuration enhances the cooling performance of the cryocooler by preventing direct radiant heat from reaching the second cooling stage, thereby achieving lower temperatures and improved refrigeration capacity compared to conventional designs.

Implementation Method 1

a radiation shield which accommodates the second cooling stage and shields the second cooling stage from radiant heat from the outside

Methodology Applied

Scientific EffectRadiant heat blocking: Thermal Radiation

Implementation Method 2

A working gas is supplied into the first cylinder and the second cylinder to be expanded and is exhausted to an outside, and thus, the first cooling stage is cooled to a first cooling temperature, and the second cooling stage is cooled to a second cooling temperature

Methodology Applied

Scientific EffectGas expansion cooling: Adiabatic Cooling

Data Source

PatentUS11566821B2Cryocooler

Publication Date: 2023.01.31 SUMITOMO HEAVY IND LTD

AI summary

A cryocooler includes a first cylinder and a second cylinder, a first cooling stage, a second cooling stage, a radiation shield which is cooled by the first cooling stage, accommodates the second cooling stage, and shields the second cooling stage from radiant heat from an outside, and a temperature sensor which detects a temperature of the second cooling stage. A working gas is supplied into the first cylinder and the second cylinder to be expanded and is exhausted to the outside, an insertion hole through which an output cable of the temperature sensor passes through from an inside to an outside of the radiation shield is provided in the radiation shield, and the insertion hole is configured such that the radiant heat entering the radiation shield from the outside of the radiation shield is not directly radiated to the second cooling stage.