Asymmetrical Scroll Compressor Injection Port Timing
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Solution Overview
Problem
Asymmetrical scroll compressors face inefficiencies due to unbalanced refrigerant injection between compression chambers, leading to reduced heating capacity and compressor reliability, especially when liquid refrigerant is introduced into the compression chamber, causing oil wash and wear on components.
Innovation Solution
The design includes a fixed scroll with a first spiral wrap and an orbiting scroll with a second spiral wrap, where the suction volume of the first compression chamber is greater than the second, with at least one injection port open during the compression stroke after suction, allowing more refrigerant to be injected into the first compression chamber, and an oil reservoir supplies oil through a back-pressure chamber to both compression chambers, ensuring efficient refrigerant injection and maintaining a stable sliding state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the intermediate pressure is increased to increase the injection rate, then the injection rate increases, but the gas-phase component ratio decreases and liquid refrigerant flows to the injection pipe
Solution Approach 1:
The gas-liquid separator performs preliminary separation of gas and liquid refrigerant before injection. The expansion valve upstream of the separator performs preliminary flashing to generate gas-phase refrigerant, ensuring that only gas-phase refrigerant is injected into the compression chamber, preventing oil wash while maintaining high injection rate
Solution Approach 2:
The gas-liquid separator acts as an intermediary device between the expansion valve and the injection pipe. It mediates the refrigerant flow by separating gas and liquid phases, allowing the injection system to operate at high intermediate pressure without directly injecting liquid refrigerant into the compression chamber
2Productivity
If the injection port is open early to allow refrigerant injection, then the injection rate increases, but the compression chamber pressure balance is disrupted
Solution Approach 1:
The injection port timing is dynamically controlled to open after the compression chamber is sealed but during the compression stroke. This dynamic timing adjustment allows refrigerant injection to occur when the chamber is isolated from the suction port, preventing pressure balance disruption while enabling high injection rate
3Productivity
If liquid refrigerant is injected to the compression chamber to increase capacity, then the heating capacity improves, but the oil is washed and sliding parts are worn
Solution Approach 1:
The liquid refrigerant is extracted and separated from the gas-phase refrigerant before injection into the compression chamber. The gas-liquid separator removes the harmful liquid phase while retaining the useful gas-phase refrigerant for injection, preventing oil wash while maintaining the capacity-enhancing injection effect
Solution Approach 2:
The expansion valve's flashing process, which initially creates liquid refrigerant that could be harmful, is converted into a benefit by using it to generate gas-phase refrigerant through flash evaporation. The liquid refrigerant that would otherwise cause oil wash is transformed into useful gas-phase injection refrigerant
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 maximizes the injection cycle effect, improves efficiency, and enhances capacity by ensuring a higher injection rate and maintaining compressor reliability through balanced internal pressures and reduced oil wash, thus stabilizing the orbiting scroll's behavior.
Implementation Method 1
In the refrigerant introduced into the compression chamber from an injection pipe, the gas refrigerant is preferentially extracted from a gas-liquid separator and is fed
Implementation Method 2
The intermediate pressure is controlled by adjusting an opening degree of the expansion valves respectively provided upstream or downstream of the gas-liquid separator
Implementation Method 3
an injection refrigerant is fed into the compression chamber by a pressure difference between the intermediate pressure and the internal pressure of the compression chamber in the compressor to which the injection pipe is finally connected
Implementation Method 4
a compressor is used which sucks a gas refrigerant evaporated by an evaporator, compresses the gas refrigerant to a pressure required for condensation by a condenser
Data Source
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AI summary
In an asymmetrical scroll compressor, at least one injection port (43) through which an intermediate-pressure refrigerant is injected into a first compression chamber (15a) and a second compression chamber (15b), at least one injection port penetrating an end plate of a fixed scroll (12) at a position where the injection port is open to the first compression chamber (15a) or the second compression chamber (15b) during a compression stroke after a suction refrigerant is introduced and closed. Further, the amount of a refrigerant injected from an injection port (43) into the first compression chamber (15a) is made more than the amount of a refrigerant injected from the injection port (43) into the second compression chamber (15b).