Scroll Compressor Back Pressure Passage for Vapor Injection Stability
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Solution Overview
Problem
Enhanced vapor injection scroll compressors face issues with the orbiting scroll overturning due to insufficient back pressure during high-pressure-ratio operations, leading to reduced efficiency and leakage between the orbiting and fixed scrolls.
Innovation Solution
The introduction of medium pressure passages that connect the compression cavity with a back pressure chamber, guiding medium pressure to the back pressure chamber to prevent scroll separation and ensure axial sealing, thereby increasing back pressure and stabilizing the compressor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If enhanced vapor injection is activated to raise compression ratio, then compressor performance under high-pressure-ratio conditions is improved, but back pressure becomes insufficient causing orbiting scroll overturning
Solution Approach 1:
The patent segments the pressure control function by introducing a dedicated back pressure chamber separated from the compression cavity, with independent pressure regulation through the back pressure passage. This allows the back pressure chamber to maintain stable pressure independently while the compression cavity experiences high-pressure-ratio conditions during vapor injection.
Solution Approach 2:
The back pressure passage acts as an intermediary element that transfers pressure from the compression cavity to the back pressure chamber. This intermediary mechanism ensures that pressure changes in the compression cavity are communicated to the back pressure chamber, maintaining scroll stability without directly affecting the high-pressure-ratio compression process.
2Reliability
If guiding passage connects compression cavity to back pressure space, then orbiting scroll overturning is prevented, but during air injection pressure connection is lost reducing efficiency
Solution Approach 1:
The patent implements a dynamic pressure connection system where the back pressure passage enables continuous pressure communication between the compression cavity and back pressure chamber. This dynamic connection ensures that back pressure is maintained throughout the compression cycle, including during air injection phases, preventing scroll overturning while maintaining efficiency.
Solution Approach 2:
The back pressure passage ensures continuous pressure transmission from the compression cavity to the back pressure chamber throughout the entire compression cycle. This continuous pressure action prevents intermittent loss of back pressure that would occur with traditional guiding passages, maintaining both scroll stability and compressor efficiency during all operating phases.
3Loss of time
If back pressure chamber pressure increases rapidly, then time to reach steady state is reduced, but scroll separation may occur without proper pressure guidance
Solution Approach 1:
The back pressure passage is pre-configured to enable rapid pressure transmission from the compression cavity to the back pressure chamber. This preliminary pressure guidance mechanism ensures that back pressure builds up quickly and uniformly, allowing the system to reach steady state rapidly while maintaining reliable axial sealing between the scrolls.
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 solution prevents scroll overturning, enhances axial sealing, and reduces the time for the compressor to reach a steady state by rapidly increasing pressure in the back pressure chamber, improving overall performance under high-pressure-ratio conditions.
Implementation Method 1
at least one of a first medium pressure passage and a second medium pressure passage... connecting the compression cavity with the back pressure chamber
Data Source
Figure 1
Figure 2(a)~2(c)
Figure 3~4
AI summary
Provided are an air injection enthalpy-increasing scroll compressor, and a refrigeration system comprising the air injection enthalpy-increasing scroll compressor. The air injection enthalpy-increasing scroll compressor comprises a compressor housing, a main frame (13), a movable scroll plate (12) and a stationary scroll plate (11). The movable scroll plate (12) is arranged on the main frame (13). The movable scroll plate (12) comprises a movable plate end plate (121) and a movable scroll tooth (122) arranged on a side end face, away from the main frame (13), of the movable plate end plate (121), with a back pressure chamber being defined between the movable plate end plate (121) and the main frame (13). The stationary scroll plate (11) is arranged on one side, away from the main frame (13), of the movable scroll plate (12). The stationary scroll plate (11) comprises a fixed scroll end plate (111) and a stationary scroll tooth (112) arranged on a side end face, adjacent to the main frame (13), of the fixed scroll end plate (111). The stationary scroll tooth (112) and the movable scroll tooth (122) are engaged with each other to form a crescent-shaped compression cavity. At least one of the movable scroll plate (12) and the stationary scroll plate (11) is provided with medium pressure passages (30, 40), and during the rotation of the movable scroll plate (12), the medium pressure passages (30, 40) are suitable for communicating the compression cavity with the back pressure chamber. The air injection enthalpy-increasing scroll compressor can inhibit the overturning of the moving scroll plate (12) during operation, thereby improving the performance of the air injection enthalpy-increasing scroll compressor.