Compressor Stator Core Cut Layout for Low Pressure Loss
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Solution Overview
Problem
Existing compressors face challenges in reducing pressure loss while maintaining motor performance as they increase in capacity, leading to increased oil loss.
Innovation Solution
A compressor design with a stator core featuring core cuts that maintain a pressure loss ratio of 1.45 or less relative to the density difference between refrigerant and lubricant, utilizing insulating members to smooth transitions in the refrigerant passage, thereby reducing sudden changes in cross-sectional area and pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a compressor is used in a heat pump water heater, then heating performance is improved, but the compressor is sensitive to liquid refrigerant which causes reliability issues
Solution Approach 1:
A liquid refrigerant bypass channel is introduced as an intermediary mechanism. This channel allows liquid refrigerant to bypass the compressor during certain operating conditions, preventing liquid refrigerant from entering the compressor while still allowing the compressor to provide heating performance. The bypass channel acts as a mediator that protects the compressor from liquid refrigerant damage.
Solution Approach 2:
The refrigerant flow path is segmented into different channels: a main channel through the compressor and a bypass channel around the compressor. This segmentation allows the system to direct liquid refrigerant through the bypass channel while gaseous refrigerant flows through the compressor, thereby protecting the compressor from liquid damage while maintaining heating functionality.
2Reliability
If the liquid refrigerant bypass channel is opened, then liquid refrigerant can bypass the compressor, but the channel may become clogged by impurities
Solution Approach 1:
Different sections of the bypass channel have different structural characteristics. The channel includes a widened portion and a narrowed portion with specific geometric features. Impurity blocking portions are strategically positioned in the narrowed sections where they can be contained, while the widened sections allow smooth refrigerant flow. This local variation in channel geometry optimizes both flow efficiency and impurity management.
Solution Approach 2:
Impurities in the refrigerant that would normally be harmful are converted into a beneficial function. The impurity blocking portions are designed to capture and retain impurities within the bypass channel, preventing them from causing damage elsewhere in the system. The impurities are thus transformed from harmful contaminants into blocked elements that are contained in a controlled location.
3Ease of manufacture
If the bypass channel has uniform cross-section, then manufacturing is simple, but liquid refrigerant flow and impurity blocking are not optimized
Solution Approach 1:
The bypass channel features non-uniform cross-sectional areas with specifically designed widened and narrowed portions. The widened portions optimize liquid refrigerant flow by reducing velocity and preventing cavitation, while the narrowed portions create velocity increases that help flush the channel and prevent impurity accumulation. This localized variation in geometry optimizes both flow efficiency and impurity management while remaining manufacturable.
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 design effectively reduces oil loss and maintains motor performance even at higher capacities by minimizing pressure loss and ensuring efficient lubricant return.
Implementation Method 1
a liquid refrigerant bypass channel configured to allow the liquid refrigerant to bypass the compressor
Implementation Method 2
a portion of the liquid refrigerant is flashed into refrigerant gas as the liquid refrigerant passes through the expansion device
Implementation Method 3
a portion of the liquid refrigerant is flashed into refrigerant gas
Data Source
Figure 1
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AI summary
A compressor (10) includes a closed container (1), a motor (2), and a compression mechanism (3), and has a circulation amount of 1000 [kg/hr] or more in an operation at a maximum number of revolutions. The motor (2) has a rotor (21) on a shaft (4) extending in an up-down direction and a stator (22) fixed to the closed container (1). The compression mechanism (3) is arranged below the motor (2) in the closed container (1). The stator (22) includes a stator core (41) provided with a core cut (46) serving as a passage (13) of a refrigerant between an inner wall of the closed container (1) and the stator (22). In the compressor (10), (the pressure loss that occurs between an inlet (46a) and an outlet (46b) of the core cut (46))/(a gas density of the refrigerant - a density of a lubricant) is 1.45 or less.