Two-Stage Compressor Oil Return Without a Separate Oil Separator
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Solution Overview
Problem
Two-stage compression devices with serially connected compressors face increased complexity, cost, and size due to the need for oil separators to manage lubricating oil, especially when using low pressure housing-type compressors as both the low and high stage-side compressors.
Innovation Solution
The lubricating oil is separated and accumulated in the low-pressure housing and directly used in the high-pressure housing-type compressor, eliminating the need for an oil separator by utilizing the high-pressure housing to separate oil from refrigerant gas and partly returning it to the low-pressure housing, reducing the number of components and simplifying the configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an oil separator is installed in the downstream of the discharge pipe of the high stage-side compressor to return oil to each compressor, then the compressors can be lubricated properly, but the structure becomes more complicated, cost increases, and unit size increases
Solution Approach 1:
The patent merges the oil separator function with the high-pressure housing of the high stage-side compressor. The high-pressure housing serves dual purposes: containing the compression chamber and functioning as an oil separator. Oil discharged from the compression chamber is separated from refrigerant gas within the high-pressure housing, eliminating the need for a separate oil separator component.
Solution Approach 2:
The high-pressure housing is designed to perform multiple functions simultaneously: it contains the compression chamber, separates oil from refrigerant gas, stores separated oil in an oil sump, and returns oil to compressors through an oil return pipe. This multi-functionality reduces the overall number of components required in the system.
2Reliability
If an oil separator is installed to return oil to each compressor, then proper lubrication is maintained, but the cost increases
Solution Approach 1:
The patent combines the oil separator functionality into the existing high-pressure housing structure, eliminating the need for a separate oil separator component. This merging reduces part count, simplifies manufacturing processes, and lowers overall system cost while maintaining effective oil return to compressors.
Solution Approach 2:
The high-pressure housing is designed to perform multiple functions including oil separation and oil return, replacing what would traditionally require multiple separate components. This multi-functionality reduces material costs, assembly costs, and maintenance costs associated with additional parts.
3Reliability
If an oil separator is installed to return oil to each compressor, then proper lubrication is maintained, but the unit size increases
Solution Approach 1:
The patent integrates the oil separator function within the high-pressure housing volume, rather than adding a separate oil separator component that would increase overall unit size. The oil sump is formed within the existing housing space, efficiently utilizing available volume.
Solution Approach 2:
The oil separation and storage functionality is nested within the high-pressure housing structure. The oil sump is contained within the housing volume, and the oil return system is integrated into the existing component layout, minimizing additional space requirements.
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 results in a more compact, cost-effective two-stage compression device with reduced oil outflow, enhancing the efficiency and performance of chilling/air-conditioning systems by eliminating the need for additional components and improving heat exchange efficiency in condensers and evaporators.
Implementation Method 1
separated from the high-pressure refrigerant gas due to a change in velocity, collision with internal components, etc. at the time of being discharged
Implementation Method 2
separated from the high-pressure refrigerant gas due to a change in velocity, collision with internal components, etc. at the time of being discharged
Implementation Method 3
The lubricating oil returned along with sucked refrigerant gas to the low stage-side compressor is separated inside a low-pressure housing and accumulated in its oil sump
Data Source
Figure 1
AI summary
There are provided a two-stage compression device having two serially connected compressors, of which the number of components is reduced through omission of an oil separator, and thereby the configuration is made simpler, lower in cost, and more compact, and a chilling/air-conditioning device using the two-stage compression device. The two-stage compression device 2 which compresses a refrigerant in two stages includes two serially connected compressors of which a low stage-side compressor 10 and a high stage-side compressor 20 in which, of the two compressors 2, the low stage-side compressor 10 is a low pressure housing-type compressor 10, while the high stage-side compressor 20 is a high pressure housing-type compressor 20, and an oil sump 25 of the high pressure housing-type compressor 20 and an oil sump 15 of the low pressure housing-type compressor 10 are connected through an oil return pipe 27.