Device and method for cooling and/or low-temperature liquefaction
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Solution Overview
Problem
Conventional low-temperature liquefaction and refrigeration devices using helium require multiple compression stages and suffer from significant gas leaks and contamination issues due to lubricating oil, leading to increased costs and inefficiencies.
Innovation Solution
The device employs a mechanical gearbox with a gaseous atmosphere of lower mean molar mass, primarily helium, to reduce mechanical losses and incorporates a buffer gas injection system to collect and purify leaked helium, separating it from oil and contaminants, and recirculating it to minimize losses and contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional lubricating oil is used in the mechanical gearbox, then mechanical losses are reduced through proper lubrication, but the working gas becomes contaminated with oil and moisture
Solution Approach 1:
The patent introduces a gaseous atmosphere (buffer gas) as an intermediary medium between the lubricating oil and the working gas. This buffer gas layer prevents direct contact and contamination while allowing the oil to perform its lubrication function. The buffer gas acts as a protective barrier that transmits mechanical power while isolating the working gas from harmful contaminants.
Solution Approach 2:
The patent creates an inert gaseous environment within the mechanical gearbox by filling it with a buffer gas that does not react with the lubricating oil or the working gas. This inert atmosphere prevents contamination of the working gas while maintaining effective lubrication, as the buffer gas remains chemically inactive and forms a stable protective layer.
2Loss of substance
If sealing components such as packings, oil seals, or gas seals are installed at each bearing to limit gas leaks, then gas loss is reduced, but device complexity and cost increase
Solution Approach 1:
The patent extracts and removes the complex sealing components (packings, oil seals, gas seals) from the system by replacing them with a simpler buffer gas atmosphere approach. Instead of installing multiple sealing elements at each bearing, the solution extracts the sealing function and achieves it through the buoyancy-based buffer gas system, significantly reducing device complexity.
Solution Approach 2:
The patent replaces the mechanical sealing system with a buoyancy-based gas barrier system. Instead of using mechanical seals that require precise fitting and maintenance, the solution substitutes them with a lighter buffer gas atmosphere that naturally forms a barrier against gas leaks through density differences, eliminating complex mechanical sealing components.
3Productivity
If multiple compression stages are used to achieve the required compression ratio, then compression efficiency is improved, but the number of bearings and potential leak points increases
Solution Approach 1:
The patent merges the sealing function across all compression stages by implementing a unified buffer gas atmosphere system throughout the mechanical gearbox. Instead of addressing sealing at each individual bearing separately, the solution combines all bearings into a single gaseous environment where the buffer gas provides continuous protection against leaks, reducing the number of discrete sealing points.
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 reduces mechanical losses, improves efficiency, and simplifies the sealing system, lowering costs and maintaining the purity of the working gas, thereby enhancing the overall performance and reducing the economic burden of helium recovery.
Implementation Method 1
the internal volume of the mechanical gearbox contains a gaseous atmosphere consisting of a gaseous mixture having a mean molar mass lower than the molar mass of air
Implementation Method 2
a buffer gas may be injected to collect the helium leaks
Data Source
AI summary
The invention relates to a device for cooling and/or liquefying, at a low-temperature, a working fluid containing helium or consisting of pure helium. The device includes a working circuit provided with a compressor station and a cold box. The compressor station includes one or more compression stages, each using one or more compressors that include a compressor wheel rigidly connected to an axle that is rotatably mounted on bearings. The axle of each compressor is rotated by an output shaft of a motor via a gear mechanism placed in a mechanical housing including lubricating oil. Said device is characterized in that the inner space of the mechanical housing contains a gaseous atmosphere consisting of a gaseous mixture having a mean molar mass that smaller than the molar mass of the air.