Two-Stage Mixed-Flow Compressor for Compact Refrigeration
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Solution Overview
Problem
Rotary compressors used in refrigeration systems with new low-pressure refrigerants require a large diameter to accommodate high speeds, exceeding available packaging space, necessitating a compressor with a reduced footprint.
Innovation Solution
A multi-stage compressor design featuring two mixed-flow compression stages with a motor section between them, where the first and second compression components are coaxial and mounted on a drive shaft, and include diffuser sections to manage fluid flow efficiently, allowing for a compact configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a centrifugal compressor is designed with high rotation speeds to accommodate new low-pressure refrigerants, then the compression performance is improved, but the overall diameter of the compressor becomes large, exceeding the available packaging space
Solution Approach 1:
The compressor is divided into two separate compression stages, each with its own impeller mounted on the same drive shaft. The first impeller compresses the refrigerant to an intermediate pressure, and the second impeller further compresses it to the final pressure. This segmentation allows each impeller to operate at optimized speeds with smaller diameters, reducing the overall footprint while maintaining high compression performance for low-pressure refrigerants
Solution Approach 2:
The patent transitions from a single-stage radial flow configuration to a two-stage axial flow configuration with impellers arranged along the axial dimension. By stacking compression stages axially rather than radially, the design reduces the overall diameter of the compressor while achieving the necessary compression ratio for low-pressure refrigerants through multiple sequential compression steps
2Productivity
If a two-stage compression system is implemented, then the compression ratio is improved, but the device complexity increases due to additional components and longer fluid flow paths
Solution Approach 1:
The motor section is positioned between the two compression stages, allowing the drive shaft to directly power both impellers without requiring separate motors or complex transmission mechanisms. The housing integrates multiple functions including structural support, fluid flow path definition, and mounting for all components. This merging of functions reduces the number of separate components and simplifies the overall system architecture despite the two-stage compression requirement
Solution Approach 2:
The housing serves multiple functions simultaneously: it provides the structural framework for the entire compressor, defines the fluid flow paths between stages, houses the motor section, and provides mounting surfaces for all components. The drive shaft serves both to rotate the first impeller and the second impeller. This multi-functionality reduces the number of dedicated components needed, thereby reducing overall system complexity while achieving high compression ratios
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 design achieves a reduced footprint while maintaining efficient fluid compression, suitable for low-pressure refrigerant applications, by optimizing the fluid flow path and compression stages within a compact housing.
Implementation Method 1
Rotation of the impeller increases a pressure and/or velocity of a fluid or gas moving across the impeller
Implementation Method 2
at least one diffuser section. The at least one diffuser section may be arranged within the housing at a position axially downstream from an outlet of the first compression component
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A compressor is provided including a housing. A first compression stage is defined within the housing and a second compression stage is defined within the housing. The first compression stage has a first compression component and the second compression stage has a second compression component. Both the first compression stage and the second compression stage have a mixed-flow configuration. A motor section is disposed between the first compression stage and the second compression stage relative to a fluid flow through the compressor.