Rotary Compressor Casing Volume Ratio for High-Speed Oil Separation
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Solution Overview
Problem
Existing rotary compressors fail to sufficiently separate lubricant oil from refrigerant at high speeds, leading to increased oil discharge and reduced reliability.
Innovation Solution
A rotary compressor design with specific spatial volume ratios defined by (A+B)*D²/(Vcc*Nmax) ensures effective oil separation even at high speeds, incorporating a variable-speed electric motor and optimized casing dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the compressor is downsized and operated at high speed, then productivity is improved, but lubricant oil separation becomes insufficient and reliability deteriorates
Solution Approach 1:
The patent changes the geometric parameters of the casing, specifically setting the volume ratio of the upper space to total volume between 0.25-0.65 and the lower space to total volume between 0.35-0.75. This parameter optimization ensures sufficient oil separation even at high operating speeds, resolving the contradiction between productivity improvement through speed increase and reliability maintenance through effective oil separation.
2Reliability
If the electric motor height is increased to ensure oil separation space, then reliability is improved, but the casing size increases
Solution Approach 1:
The patent optimizes the height parameters by defining L1/(L1+L2) between 0.25-0.65, where L1 is the upper space height and L2 is the motor height. This allows sufficient oil separation space while controlling the overall motor and casing size, preventing upsizing of the casing while ensuring reliable oil separation.
Solution Approach 2:
The patent utilizes the axial dimension of the casing by creating distinct upper and lower spaces with optimized volume ratios. This dimensional approach allows effective oil separation without increasing the radial size of the casing, thus avoiding upsizing while maintaining reliability.
3Volume of moving object
If the compressor is downsized, then the casing volume is reduced, but the flow velocity increases and oil separation becomes insufficient
Solution Approach 1:
The patent optimizes the volume ratios of the upper and lower spaces within the casing. By setting the upper space volume ratio between 0.25-0.65 and the lower space volume ratio between 0.35-0.75, the patent ensures sufficient oil separation capacity even in a downsized casing with higher flow velocities, thus maintaining reliability while achieving downsizing.
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 reduces oil loss and vibration, maintaining compressor reliability and efficiency, even when downsized and operated at high speeds.
Implementation Method 1
an electric motor (40) that is a variable-speed type electric motor and that is disposed in the casing (20)
Implementation Method 2
a compression mechanism (30) that is disposed in the casing (20) and that is coupled with the electric motor (40)
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A relationship represented by 0.8 ≤ (A+B)*D2/(Vcc*Nmax) ≤ 1.0 is satisfied, where the axial length of the first space (S 1) is A, the axial length of the second space (S2) is B, the inner diameter of the casing (20) is D, the suction volume per rotation of the compression mechanism (30) is Vcc, and the maximum rotational speed of the compression mechanism (30) is Nmax.