Cryogenic Bellows Pump Design for High-Pressure Magnetic Refrigeration

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing cryogenic pumps, such as those using bellows, face challenges in withstanding high operating pressures due to their structural limitations, leading to high costs and complexity, especially when used in magnetic refrigeration systems requiring pressures of several atmospheres or more.

Innovation Solution

The design employs a cryogenic pump with bellows that expand and contract using external pressure, rather than internal, allowing for increased pressure resistance and simplified structure, utilizing commercial components to achieve high operating pressures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If bellows are used as cryogenic pumps, then the pump can operate at low temperatures, but the pressure resistance is limited to several atmospheres

Engineering Contradiction:

Improveoperating temperatureVSAvoidpressure resistance

Core Design Contradiction:

TemperatureVSStress or pressure

Solution Approach 1:

The patent inverts the conventional bellows pressure application method. Instead of applying pressure from the inside (internal pressure), the invention applies pressure from the outside (external pressure) to the bellows. This inversion allows the bellows to withstand much higher pressures while maintaining their flexibility and cryogenic operation capability, resolving the contradiction between low-temperature operation and pressure resistance.

Inventive Principle:

Principle #13The other way round (Inversion)

2Stress or pressure

If high pressure resistance is achieved using conventional bellows, then the pump can withstand high operating pressures, but the structure becomes complex and costly

Engineering Contradiction:

Improvepressure resistanceVSAvoidstructural complexity

Core Design Contradiction:

Stress or pressureVSDevice complexity

Solution Approach 1:

By inverting the pressure application method from internal to external, the patent simplifies the bellows structure. The external pressure application eliminates the need for complex reinforcement structures, multi-layer constructions, or specialized high-pressure bellows designs. This approach achieves high pressure resistance (capable of withstanding 10 atmospheres or more) while maintaining a simple, commercially viable structure.

Inventive Principle:

Principle #13The other way round (Inversion)

3Device complexity

If room temperature pumps are used, then the pump system is simple and cost-effective, but the power consumption increases and energy efficiency decreases

Engineering Contradiction:

Improvesystem simplicityVSAvoidpower consumption

Core Design Contradiction:

Device complexityVSUse of energy by moving object

Solution Approach 1:

The patent replaces the conventional room-temperature mechanical pump system with a cryogenic pump system that operates at low temperatures. This substitution eliminates the need for thermal management of the pump itself, reduces power consumption, and improves overall energy efficiency of the magnetic refrigeration system while maintaining operational simplicity through the external pressure bellows design.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical 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

This approach results in a compact, cost-effective, and stable operation of magnetic refrigeration devices, overcoming the limitations of traditional cryogenic pumps by using commercially available components and reducing complexity.

Implementation Method 1

with the heat exchange gas under pressure, contained in an upper bellows chamber and a lower bellows chamber that are respectively formed on outer sides of the upper bellows and the lower bellows, the upper bellows and the lower bellows are alternately expanded and contracted

Methodology Applied

Scientific EffectExternal pressure: Pressure Increase

Implementation Method 2

a magnetic refrigerator filled with a magnetic working substance having a magnetocaloric effect

Methodology Applied

Scientific EffectMagnetocaloric effect: Magnetocaloric Effect

Data Source

PatentEP4696954A1Magnetic refrigeration device and liquefaction device using low-temperature pump

Publication Date: 2026.02.18 NAT INST FOR MATERIALS SCI

Figure 1
Figure 2
Figure 3~4

AI summary

The present invention provides a magnetic refrigerator having low power consumption, using a low-temperature pump that uses bellows. This magnetic refrigerator is a magnetic refrigeration device that cools an object to be cooled, and comprises a low-temperature pump installed inside a cryostat for circulating a heat exchange gas, a magnetic refrigerator that cools using upper and lower magnetic working substances having a magnetocaloric effect, and a drive mechanism that feeds the heat exchange gas from the low-temperature pump to the magnetic refrigerator and feeds back the heat exchange gas to the low-temperature pump, the low-temperature pump being a structure in which at least a portion of the inside of upper and lower bellows is opened to a vacuum chamber side of the cryostat, and the upper and lower bellows are expanded/contracted in a state in which pressure is applied to a bellows chamber formed outside the upper and lower bellows, and the heat exchange gas in the bellows chamber is pushed out to the magnetic refrigerator side by the drive mechanism.