Magnetic Spring Expander Unit for Stirling Cryogenic Refrigerator
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Stirling cryogenic refrigeration devices face challenges in achieving efficient cooling due to parasitic heat conduction and complexity in mechanical spring systems, which affect the compression ratio and efficiency.
Innovation Solution
A rodless pneumatic expander unit with a magnetic spring assembly and a parallel wire regenerative heat exchanger, where the magnetic spring operates on attractive and repulsive forces to restore the moving assembly to its equilibrium position, and the regenerative heat exchanger is constructed with polymeric filaments oriented parallel to the longitudinal axis to enhance heat exchange efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional mechanical springs are used in the expander unit, then the moving assembly can be restored to equilibrium position, but the device complexity increases and parasitic heat conduction occurs
Solution Approach 1:
The patent replaces the conventional mechanical spring system with a magnetic spring system. The magnetic spring assembly includes a stationary magnetic assembly and a movable magnetic assembly that interact through magnetic fields to provide the restoring force. This substitution eliminates the need for physical mechanical springs, thereby reducing device complexity and parasitic heat conduction while maintaining the essential function of restoring the moving assembly to its equilibrium position.
2Reliability
If conventional mechanical springs are used in the expander unit, then the moving assembly can be restored to equilibrium position, but parasitic heat conduction increases
Solution Approach 1:
The patent replaces the conventional mechanical spring system with a magnetic spring system. The magnetic spring assembly includes a stationary magnetic assembly and a movable magnetic assembly that interact through magnetic fields to provide the restoring force. This substitution eliminates the need for physical mechanical springs, thereby reducing device complexity and parasitic heat conduction while maintaining the essential function of restoring the moving assembly to its equilibrium position.
3Use of energy by moving object
If polymeric filaments are used in the regenerative heat exchanger, then heat exchange efficiency increases, but manufacturing complexity increases
Solution Approach 1:
The patent employs a regenerative heat exchanger constructed with polymeric filaments arranged in a porous structure. The filaments are oriented parallel to the longitudinal axis of the cold finger, creating a porous medium that allows efficient heat exchange between the gaseous working agent and the heat exchanger structure. The porous configuration increases the surface area for heat transfer while maintaining permeability to the working gas, thereby enhancing heat exchange efficiency.
Solution Approach 2:
The patent employs a regenerative heat exchanger constructed with polymeric filaments arranged in a porous structure. The filaments are oriented parallel to the longitudinal axis of the cold finger, creating a porous medium that allows efficient heat exchange between the gaseous working agent and the heat exchanger structure. The porous configuration increases the surface area for heat transfer while maintaining permeability to the working gas, thereby enhancing heat exchange efficiency.
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 reduces parasitic heat conduction, increases the efficiency of the cooling cycle, and simplifies the design by eliminating the need for mechanical springs, resulting in improved thermodynamic performance and reduced complexity.
Implementation Method 1
attractive and repulsive forces between the movable magnetic assembly and the stationary magnetic assembly yield a restoring force that is directed to restore the moving assembly to the equilibrium position
Implementation Method 2
A pneumatically actuated expansion piston (displacer), containing a porous regenerative heat exchanger, is moved back and forth within the cold finger to transfer heat from the expansion chamber to a warm chamber
Implementation Method 3
a cryocooler operates on the basis of a closed Stirling thermodynamic cycle, during which a gaseous working agent (e.g., helium, nitrogen, or another suitable, usually inert, gas) is cyclically compressed in a piston compression unit (compressor) and allowed to cyclically expand within a pneumatic expander unit while performing mechanical work
Data Source
AI summary
An expander unit of a cryogenic refrigerator device includes a moving assembly with a porous regenerative heat exchanger configured to move back and forth along a longitudinal axis. A magnetic spring assembly includes a stationary magnetic assembly fixed to the cold finger base that includes one or more magnetic rings fixedly arranged about a bore. A movable magnetic assembly includes one or more movable magnetic rings fixed to the moving assembly. An outer lateral dimension of each of the movable magnetic rings is less than an inner lateral dimension of the bore. The stationary magnetic assembly and the movable magnetic assembly are configured such that, when the moving assembly is displaced along the longitudinal axis from an equilibrium position, attractive and repulsive forces between the movable magnetic assembly and the stationary magnetic assembly yield a restoring force that is directed to restore the moving assembly to the equilibrium position.