Scroll Compressor Silencing Chamber With Asymmetric Expansion Part
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Solution Overview
Problem
Existing scroll compressors with circular cross-section discharge spaces experience reduced silencing effect due to acoustic resonance modes occurring at frequencies close to each other, leading to increased noise and potential compressor malfunction from excessive compression load.
Innovation Solution
A scroll compressor with a compression mechanism featuring a fixed scroll and orbiting scroll, including a main port, sub-ports, and a silencing chamber with a flattened expansion part that forms a sound field with rotational asymmetry, preventing antinodes from aligning with discharge holes and reducing noise through frequency separation of acoustic resonance modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the discharge space has a circular cross-section with rotational symmetry, then the structure is simple and easy to manufacture, but acoustic resonance modes occur at frequencies very close to each other, reducing the silencing effect and increasing noise
Solution Approach 1:
The patent applies asymmetry by changing the cross-sectional shape of the discharge space from circular to non-circular (such as oval or rectangular). This asymmetric geometry breaks the rotational symmetry, causing acoustic resonance modes to occur at well-separated frequencies rather than closely spaced frequencies. The asymmetric shape prevents the formation of standing waves with antinodes and nodes at problematic positions, thereby reducing noise while maintaining manufacturing feasibility
Solution Approach 2:
The patent changes the geometric parameters of the discharge space, specifically the cross-sectional shape parameters. By transitioning from a circular cross-section (with radius r) to a non-circular cross-section (such as an oval with major axis a and minor axis b, or a rectangular cross-section with width w and height h), the acoustic resonance characteristics are fundamentally altered. This parameter change shifts the resonance frequencies apart, improving the silencing effect across a broader frequency range
2Device complexity
If the expansion part has a circular cross-section, then the silencing chamber structure is simple, but acoustic resonance modes with antinodes align with discharge holes, reducing silencing effect and increasing noise
Solution Approach 1:
The patent applies asymmetry to the expansion part by changing its cross-sectional shape from circular to non-circular. This asymmetric geometry prevents acoustic resonance modes with antinodes from aligning with the discharge holes, as the standing wave patterns are disrupted. The result is reduced noise emission while the expansion part remains a simple structural component without complex internal features
Solution Approach 2:
The patent applies local quality by specifically modifying the cross-sectional shape of the expansion part while maintaining other aspects of the silencing chamber structure. The non-circular cross-section is applied locally to the expansion part to address the acoustic resonance issue at that specific location, where the standing waves are formed, without requiring changes to the entire silencing chamber structure
3Shape
If acoustic resonance modes occur at closely spaced frequencies, then the circular geometry is maintained, but the silencing effect is reduced and noise increases
Solution Approach 1:
The patent directly addresses the shape issue by transitioning from a circular cross-section to a non-circular cross-section. This asymmetric shape modification fundamentally changes the acoustic resonance characteristics, separating the resonance frequencies and preventing the closely spaced frequency phenomenon. The new shape maintains structural simplicity while effectively reducing noise through frequency separation of acoustic modes
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 silencing chamber with a flattened expansion part effectively reduces noise from refrigerant pulsations by maintaining positive noise reduction over a wide frequency band, preventing antinodes from aligning with discharge holes, and ensuring efficient operation without compromising flow rate.
Implementation Method 1
acoustic resonance mode occurs at a specific frequency. This leads to reduced silencing effect of the silencing chamber including the expansion part, and consequently to increased noise
Implementation Method 2
If the space for receiving refrigerant discharged from the compression chamber has a circular cross-section, a circular sound field is formed within an expansion part that defines the space
Data Source
AI summary
A scroll compressor includes a compression mechanism with a compression chamber. The compression chamber is a combination of a fixed scroll and an orbiting scroll, and is to compress working gas. The fixed scroll includes a main port, and a plurality of sub-ports. The main port is a port through which the working gas compressed in the compression chamber is to be discharged. The sub-ports are ports through which the working gas over-compressed in the compression chamber is to be discharged. The scroll compressor includes a rotary shaft, and a silencing chamber. The rotary shaft drives the compression mechanism. The silencing chamber is disposed downstream of the main port with respect to the flow of the working gas. The silencing chamber includes a discharge hole, an expansion part, and a plurality of chamber sub-ports. The discharge hole is a hole through which the working gas is to be discharged.