Granulated particle for cold storage material particle, granulated particle group for cold storage material particles, cold storage material particle, cold storage material particle group, cold storage device, refrigerator, cryopump, superconducting magnet, nuclear magnetic resonance imaging apparatus, nuclear magnetic resonance apparatus, magnetic field application type single crystal pulling apparatus, helium re-condensing device, and dilution refrigerator
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Solution Overview
Problem
Conventional cold storage materials face challenges in achieving high-density filling and maintaining a large contact area with helium gas, leading to reduced refrigeration performance and increased helium consumption, while also being prone to clogging and mechanical weakness.
Innovation Solution
The development of granulated particles with recesses on their surface, made from rare earth oxysulfides or oxides, which enhance specific surface area and mechanical strength, allowing for improved helium contact and thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional cold storage material particles are used, then filling density can be increased, but contact area with helium gas decreases and refrigeration performance deteriorates
Solution Approach 1:
The particle surface is designed with recesses (depressions) that create a porous-like structure, increasing the effective contact area with helium gas while maintaining high filling density. The recesses allow helium to penetrate and contact more surface area of the particle.
Solution Approach 2:
The invention transitions from a smooth 2D surface to a 3D surface with recesses, effectively increasing the surface area without significantly increasing particle volume. This dimensional complexity allows more helium contact area within the same filling space.
2Area of stationary object
If particle size is reduced to increase surface area, then helium contact improves, but mechanical strength decreases and clogging occurs
Solution Approach 1:
The recesses are strategically positioned and sized on the particle surface, creating local variations in geometry that increase surface area without compromising the overall structural integrity. The recesses provide surface area enhancement while the main particle body maintains sufficient mechanical strength.
Solution Approach 2:
The particle consists of a core material with a surface structure modification (recesses), creating a composite structure that combines the mechanical strength of the core material with the enhanced surface area of the recessed structure.
3Quantity of substance
If smooth spherical particles are used, then filling density is maximized, but thermal conductivity and heat exchange efficiency decrease
Solution Approach 1:
The recesses create a micro-porous surface structure that enhances thermal exchange between the particle and helium gas. The increased surface area and micro-cavities improve heat transfer efficiency while maintaining good filling density.
Solution Approach 2:
The particle maintains a generally spherical shape for optimal packing, but introduces controlled curvatures in the form of recesses on the surface. This combines the benefits of spherical packing with enhanced thermal exchange surfaces.
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 granulated particles with surface recesses increase refrigeration performance by enhancing helium contact and thermal conductivity, while maintaining mechanical integrity and preventing clogging, thus reducing helium consumption and improving refrigeration efficiency.
Implementation Method 1
the cold storage material desirably has a high thermal conductivity
Implementation Method 2
cold is generated by heat exchange between the cold storage material and helium gas passing through the cold storage device
Data Source
AI summary
A granulated particle for cold storage material particle according to an embodiment includes a rare earth oxysulfide or a rare earth oxide containing at least one rare earth element selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, in which the granulated particle has a plurality of recesses each having a closed curve at an outer edge on a surface thereof.