Scroll Compressor Capacity Control via Segmented Back Pressure
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Solution Overview
Problem
Conventional scroll compressors face limitations in reducing capacity variation ratio, leading to increased frictional loss and complexity in structure, which affects efficiency and refrigerant leakage during power saving operations.
Innovation Solution
The implementation of a scroll compressor design with a plurality of back pressure holes formed at regular intervals, independently opened and closed to control the back pressure chamber pressure, and a bypass valve system to manage refrigerant flow between compression chambers, allowing for efficient capacity variation and reduced friction loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the bypass hole is moved toward the discharge port to reduce capacity variation ratio, then the capacity control precision is improved, but the frictional loss increases and compressor efficiency decreases
Solution Approach 1:
The patent divides the single back pressure hole into multiple back pressure holes (first back pressure hole and second back pressure hole) positioned at different locations. This segmentation allows independent control of pressure in different regions, enabling precise capacity variation without requiring the bypass hole to be positioned optimally for both regions simultaneously, thus avoiding the frictional loss increase that would result from moving the bypass hole toward the discharge port.
2Reliability
If the back pressure hole is moved toward the discharge port to ensure sealing force during power saving operation, then the sealing performance is improved, but the frictional loss during power operation increases
Solution Approach 1:
The patent applies local quality by positioning different back pressure holes at different locations corresponding to different functional requirements. The first back pressure hole is positioned to ensure sealing force during power saving operation, while the second back pressure hole is positioned to reduce frictional loss during power operation. This localized differentiation allows each region to optimize for its specific function without compromising overall system performance.
3Stability of the object's composition
If the modulation ring is formed in an annular shape with control valve engagement, then the structural stability is improved, but the capacity variation speed decreases and weight increases
Solution Approach 1:
The patent extracts the control valve engagement function from the modulation ring structure. Instead of having the modulation ring formed in an annular shape with integrated control valve engagement (which increases weight and reduces responsiveness), the invention uses a simplified modulation ring that works in conjunction with separately positioned back pressure holes and valves. This separation allows the modulation ring to be lighter and more responsive while maintaining structural stability through the distributed back pressure hole configuration.
4Measurement precision
If the capacity variable device uses a modulation ring with multiple communication paths, then the capacity control precision is improved, but the device complexity increases
Solution Approach 1:
The patent merges the functions of multiple communication paths into a simplified configuration using the back pressure chamber assembly. Instead of implementing separate first, second, and third communication paths through a complex modulation ring structure, the invention combines these functions into a unified system where the back pressure chamber assembly integrates the pressure control and capacity variation functions. This merging reduces the number of separate components and simplifies the overall structure while maintaining precise capacity control through the coordinated operation of multiple back pressure holes.
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 enhances system efficiency by minimizing friction loss and refrigerant leakage, while simplifying the structure and reducing manufacturing costs, enabling rapid capacity variation with minimal force.
Implementation Method 1
a back pressure chamber assembly (160) provided on a rear surface of the second scroll (150) to form a back pressure chamber (160a) so as to support the second scroll (150) in the first scroll (140) direction
Implementation Method 2
a bypass hole (151b) provided between the compression chamber and an internal space of the casing (110) to bypass refrigerant suctioned into the compression chamber (P) to the internal space of the casing (110) so as to vary a compression capacity of the compression chamber (P)
Data Source
AI summary
A scroll compressor including a casing; a compression unit provided in an inner space of the casing to form a compression chamber by a pair of two scrolls; a bypass hole provided in the compression unit to bypass refrigerant suctioned into the compression chamber to the inner space of the casing; a bypass valve configured to selectively open and close the bypass hole to vary a compression capacity of the compression chamber; a back pressure chamber provided on a rear side of either one of the pair of two scrolls to support the scroll in the other scroll direction; a back pressure passage configured to communicate between the compression chamber and the back pressure chamber; and a back pressure valve configured to selectively open and close the back pressure passage.