Linear-Drive Cryogenic Refrigerator for Independent Stage Control
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Solution Overview
Problem
Conventional cryogenic refrigerators face inefficiencies due to the interdependence of their stages, where the second stage's performance is limited by the first stage, making it difficult to optimize the stroke parameters and temperature control independently, leading to oversized systems that waste energy and fail to meet varying cooling requirements.
Innovation Solution
The implementation of a cryogenic refrigerator with independent control of each stage using linear motors aligned coaxially with the displacers, allowing for distinct stroke lengths, speeds, and phases, enabling separate optimization of the first and second stages without redesigning the entire system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common rotary motor drives both first and second displacers, then the device complexity is reduced, but the ability to independently optimize stroke parameters for each stage deteriorates
Solution Approach 1:
The patent divides the drive system into separate linear motors for each stage, with the first linear motor driving the first displacer and the second linear motor driving the second displacer. This segmentation allows independent control of stroke length, speed, and phase for each stage, resolving the contradiction between device complexity and independent optimization capability.
Solution Approach 2:
The patent implements a nested configuration where the second linear motor is positioned within the first linear motor assembly, and the second displacer is positioned within the first displacer assembly. This nesting allows independent drive control while maintaining a compact structure, thus reducing overall device complexity while preserving independent stage optimization capability.
2Use of energy by moving object
If stroke parameters are changed to increase efficiency, then energy usage improves, but the need for complete system redesign increases device complexity
Solution Approach 1:
The patent implements dynamic control of stroke parameters through independently controlled linear motors, allowing stroke length, speed, and phase to be adjusted during operation without mechanical redesign. This dynamic adaptability enables energy efficiency optimization while maintaining a fixed system structure.
Solution Approach 2:
The patent enables independent adjustment of critical parameters including stroke length, stroke speed, and phase difference between stages through electronic control of linear motors. This parameter flexibility allows energy efficiency improvements without requiring physical system redesign.
3Device complexity
If the second stage depends on the first stage performance, then device complexity is reduced, but the productivity of the second stage deteriorates
Solution Approach 1:
The patent segments the drive control for each stage, with the first linear motor controlling the first displacer and the second linear motor controlling the second displacer independently. This segmentation allows the second stage to operate with optimized parameters independent of first stage performance constraints, thereby improving second stage productivity.
Solution Approach 2:
The patent enables independent parameter optimization for the second stage, including adjustable stroke length, stroke speed, and phase control relative to the first stage. This independent parameter control allows the second stage to achieve optimal productivity without being constrained by first stage performance.
4Reliability
If oversized systems are used to meet varying cooling requirements, then reliability is improved, but energy waste increases
Solution Approach 1:
The patent implements dynamic adjustment of stroke parameters and cooling capacity through independent linear motor control, allowing the system to match cooling output to actual requirements in real-time. This dynamic capability eliminates the need for oversized systems while maintaining reliability across varying load conditions.
Solution Approach 2:
The patent enables continuous adjustment of operating parameters including stroke length, stroke speed, and phase control to optimize cooling capacity for different load conditions. This parameter flexibility allows reliable meeting of varying cooling requirements without the energy waste associated with oversized fixed-capacity systems.
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 enhances efficiency by allowing independent adjustment of stroke parameters and temperature control for each stage, enabling the system to meet specific cooling demands with improved energy usage and flexibility, reducing unnecessary capacity and vibration.
Implementation Method 1
The first and second motors are linear motors
Implementation Method 2
the fluid is expanded at one end of a piston or displacer to cool a refrigeration cylinder
Data Source
Figure 1A~1D
Figure 1E
Figure 1F
AI summary
A cryogenic refrigerator has a refrigeration cylinder and at least two displacers. Each displacer reciprocates in the refrigeration cylinder and moves refrigeration gas through the refrigeration cylinder. A regenerator cools the refrigeration gas, and gas control valves admit high pressure gas into the refrigeration cylinder and exhaust gas from the refrigeration cylinder. The refrigerator also has linear motors operatively connected to displacers, and the linear motors drive the displacers in reciprocating movement. A position sensor is provided to determine a parameter of the displacers during reciprocation. A controller is operatively connected to the linear motors to control the linear motors. The controller controls a parameter of the two displacers during reciprocation. The parameter can be stroke length, stroke speed, stroke phase or another parameter of the displacer for temperature control of the cryogenic refrigerator. The cryogenic refrigerator may also include a device to remove vibration.