Scroll Compressor Communication Groove Backflow Reduction
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Solution Overview
Problem
Scroll compressors experience pulsation and noise due to refrigerant flowing back into the compression chamber from the discharge port, leading to pressure loss and increased discharge pressure variations, which existing check valve solutions do not completely eliminate and can decrease compressor efficiency.
Innovation Solution
The compression chamber is divided into first and second compression chambers with a communication groove connecting them near the wrapping start position of the scrolls, allowing gradual release of high-pressure refrigerant into the discharge port before separation, reducing backflow and stress concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a check valve is used to prevent refrigerant backflow, then backflow prevention is improved, but discharge resistance increases and compressor efficiency decreases
Solution Approach 1:
The compression chamber is divided into a first compression chamber (31a) and a second compression chamber (31b) separated by a partition wall (41c). This segmentation allows different discharge timing strategies for different compression stages, enabling backflow prevention without requiring a check valve that would impede flow for all chambers.
Solution Approach 2:
A communication groove (33) is provided in the fixed end plate (41) to preliminarily connect the first compression chamber (31a) and discharge port (32) before the outer circumferential surface of the movable wrap (37) separates from the inner circumferential surface of the fixed wrap (42). This preliminary connection allows high-pressure refrigerant to be gradually released into the discharge port before full compression completion, preventing sudden backflow while avoiding the need for a check valve.
2Ease of operation
If the discharge port is opened at the central portion of the wraps, then discharge functionality is improved, but refrigerant flows back into the compression chamber causing pulsation and noise
Solution Approach 1:
The communication groove (33) performs a preliminary discharge action by connecting the first compression chamber (31a) to the discharge port (32) before the movable wrap (37) fully separates from the fixed wrap (42). This gradual release of high-pressure refrigerant prevents sudden pressure equalization and backflow into the compression chamber, thereby eliminating pulsation and noise while maintaining the central discharge port configuration.
Solution Approach 2:
The communication groove (33) acts as an intermediary passage between the first compression chamber (31a) and the discharge port (32). It mediates the pressure transition by allowing controlled flow of high-pressure refrigerant before full compression completion, preventing direct sudden backflow that would cause harmful pulsation and noise.
3Stress or pressure
If the compression chamber is compressed to near the central portion before communicating with the discharge port, then compression ratio is improved, but pressure in the compression chamber becomes lower than discharge pressure causing backflow
Solution Approach 1:
The communication groove (33) enables preliminary communication between the first compression chamber (31a) and discharge port (32) at an optimal timing before the movable wrap (37) fully separates from the fixed wrap (42). This timing allows the compression chamber to achieve near-maximum compression ratio while maintaining pressure above discharge pressure, preventing backflow and ensuring pressure stability.
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 configuration reduces pulsation and noise by gradually releasing refrigerant, minimizing backflow into the compression chamber and distributing stress, thereby enhancing compressor efficiency and reducing noise.
Implementation Method 1
the movable scroll rotates eccentrically with respect to the fixed scroll, thereby sucking a low-temperature, low-pressure fluid into the compression chamber
Data Source
AI summary
A scroll compressor includes fixed and movable scrolls and a crank shaft coupled to the movable scroll. The fixed and movable wraps are engaged to form a compression chamber. A refrigerant compressed in the compression chamber is discharged from a discharge port open at a central portion of the fixed end plate. The compression chamber is divided into first and second compression chambers facing outer and inner circumferential surfaces of the movable wrap. One of the end plates is provided with a communication groove recessed at a portion near a wrapping start position of the wrap. The communication groove connects the first compression chamber and the discharge port before the outer circumferential surface of the movable wrap, which is eccentrically rotating while sliding on an inner circumferential surface of the fixed wrap, separates from the inner circumferential surface of the fixed wrap.