Two-stage compression cycle
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Solution Overview
Problem
Current two-stage compression systems require multiple oil separators and complex oil equalization circuits, leading to increased costs and complexity, while existing solutions with a single oil separator necessitate subtle adjustments and additional circuits to balance oil levels between compressors.
Innovation Solution
A two-stage compression system with independent first and second oil-returning circuits connected between an oil separator and both compressors, where V1 > V2, ensuring appropriate oil levels without the need for oil equalization between compressors, and allowing for easy adjustment of return-oil volumes using capillary tubes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple oil separators are provided on discharge sides of individual compressors, then oil can be separated and returned to each compressor, but the configuration becomes complicated and cost increases
Solution Approach 1:
The patent merges multiple oil separation functions into a single oil separator located on the discharge side of the higher-stage compressor. This single oil separator handles oil separation for both the higher-stage compressor and the lower-stage compressor, eliminating the need for multiple separate oil separators and their associated complex equalization circuits.
Solution Approach 2:
The single oil separator serves multiple functions: it separates oil from the discharge of the higher-stage compressor and also serves as the oil return point for both compressors through the independent oil-returning circuits. This multi-functional design simplifies the overall system configuration while maintaining reliable oil level control.
2Device complexity
If a single oil separator is provided on discharge side of higher-stage compressor, then configuration is simplified, but subtle adjustment of return-oil volume is essential to eliminate oil level imbalance
Solution Approach 1:
The patent segments the oil return path into two independent oil-returning circuits: a first oil-returning circuit for returning oil to the lower-stage compressor and a second oil-returning circuit for returning oil to the higher-stage compressor. This segmentation allows independent control and adjustment of oil flow to each compressor, eliminating the need for complex oil equalization while maintaining simple configuration.
Solution Approach 2:
The patent utilizes parameter changes in pressure difference to control oil return volumes. By designing the circuits so that the pressure difference in the first oil-returning circuit (ΔP1 = HP - LP) is always greater than the pressure difference in the second oil-returning circuit (ΔP2 = HP - MP), the system automatically achieves appropriate oil distribution without requiring subtle manual adjustments.
3Reliability
If second oil-returning circuit is provided between higher-stage and lower-stage compressors, then oil level imbalance is reduced, but configuration complexity increases
Solution Approach 1:
Instead of providing a second oil-returning circuit between the two compressors as in conventional systems, this patent segments the oil return paths by providing two independent circuits that both originate from the single oil separator on the higher-stage compressor discharge side. This approach achieves oil level balance through independent circuit design rather than through inter-compressor equalization circuits.
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
Simplifies the configuration of oil-returning circuits, ensures reliable oil levels in both compressors, and allows for efficient operation by eliminating the need for oil equalization between the lower-stage and higher-stage compressors, while enabling easy adjustment of return-oil volumes.
Implementation Method 1
easy adjustment of return-oil volumes using capillary tubes
Implementation Method 2
by making the volume V1 of the oil returned to the lower-stage compressor greater than the volume V2 of the oil returned to the higher-stage compressor
Data Source
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AI summary
An object is to provide a two-stage compression system that has no need for oil equalization between a lower-stage compressor and a higher-stage compressor, which makes it possible to simplify the configuration, and that makes it possible to reliably ensure appropriate oil levels in both the lower-stage compressor and the higher-stage compressor. In a two-stage compression system (1) in which a lower-stage compressor (2) and a higher-stage compressor (3) are disposed in series, and an oil separator (7) is provided on a discharge side of the higher-stage compressor (3), a first oil-returning circuit (11) and a second oil-returning circuit (12), which are independent of each other, are provided so as to be connected between the oil separator (7) and the lower-stage compressor (2) and the higher-stage compressor (3), and V1 > V2 is satisfied, assuming that the volume of oil returned to the lower-stage compressor (2) from the first oil-returning circuit (11) is V1, and the volume of oil returned to the higher-stage compressor (3) from the second oil-returning circuit (12) is V2.