Symmetric Linear Expander Layout for Low-Vibration Cryogenic Cooling
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Solution Overview
Problem
Conventional cryogenic expanders face issues with low efficiency, noise, and vibration due to complex mechanical structures, and turbo expanders face technical barriers from high-speed bearing requirements.
Innovation Solution
A linear expander with symmetrically positioned pistons and reed valves that convert expansion energy into electrical energy, reducing energy losses and structural vibrations, and integrating the expander into a cryogenic refrigeration system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a reciprocating expander with crank mechanism is used, then the expansion work can be discharged to the outside, but the device becomes large in size and operates at low frequency with significant noise and vibration
Solution Approach 1:
The patent extracts and removes the crank mechanism from the system, replacing it with a direct linear motion output structure. The piston's linear reciprocating motion is directly transmitted to the working mechanism without conversion through crank, cam, or other intermediate mechanical components, thereby eliminating the associated noise, vibration, and structural complexity while maintaining expansion work discharge capability
Solution Approach 2:
Instead of converting linear motion to rotational motion through crank mechanism as in conventional expanders, the patent inverts the approach by directly utilizing the linear reciprocating motion of the piston for work discharge. This inversion of the motion conversion principle simplifies the mechanical structure and reduces operational complexity
2Loss of energy
If a turbo expander with high-speed impeller is used, then the expansion efficiency is excellent, but the technical barrier arises from requiring bearing technology to support several kilohertz rotation speed
Solution Approach 1:
The patent replaces the high-speed rotating impeller mechanism with a linear reciprocating piston system. By substituting rotational mechanics with linear mechanics, the system achieves comparable expansion efficiency without requiring complex high-speed bearing technology, thus eliminating the technical barrier associated with kilohertz-range rotation support
Solution Approach 2:
The patent transitions from a static bearing support system required for high-speed rotation to a dynamic linear reciprocating system where the piston moves back and forth along a linear path. This dynamic approach allows the system to achieve high expansion efficiency without the need for sophisticated high-speed bearing technology, as the linear motion can be supported by simpler guide structures
3Ease of operation
If a conventional reciprocating expander with crank is used, then the linear motion can be converted to rotational motion, but noise and vibration are generated and efficiency is reduced due to leakage and thermal losses
Solution Approach 1:
The patent extracts and eliminates the crank mechanism that causes energy losses through leakage and thermal effects. By removing this intermediate conversion component, the system maintains a sealed configuration that prevents gas leakage and reduces thermal losses between different pressure zones, thereby improving overall energy efficiency while still achieving the desired motion conversion through direct linear actuation
4Power
If a reciprocating expander with internal and external temperature and pressure differences is used, then the expansion process can be performed, but leakage occurs and thermal losses increase reducing efficiency
Solution Approach 1:
The patent merges the high-pressure and low-pressure zones into a more integrated configuration where the piston directly separates and moves between the two zones without intermediate mechanical components. This merging approach reduces the number of sealing interfaces and thermal bridges, thereby minimizing leakage and thermal losses while maintaining the expansion process functionality
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 linear expander effectively offsets vibration and noise, simplifies the piston structure, and reduces energy losses by converting expansion energy into electrical energy, enhancing efficiency and operational frequency.
Implementation Method 1
first and second linear generating portions respectively causing pistons provided in the first hole and the second hole to linearly reciprocate to generate an induced electromotive force with an expansion force generated when the fluid having the first pressure expands to the fluid having the second pressure
Implementation Method 2
A reverse Brayton system operates with processes of compression, cooling, expansion and heating, and generates refrigeration work by adiabatic expansion of working gas
Data Source
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AI summary
The present invention relates to a linear expander that can structurally offset vibration and noise caused from piston movement by moving pistons combined to two linear generators symmetrically provided in a body portion where a suction valve and a discharge valve are respectively provided to bilaterally opposite directions, and accordingly the expander has a simple structure and motion stability of the compressor can be improved.