Scroll Compressor Discharge Valve Backflow Control
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Solution Overview
Problem
Conventional scroll compressors face issues with reverse flow of refrigerant, reverse rotation of the orbiting scroll, and oil level reduction when the compressor operates under conditions exceeding the designed compression ratio, leading to efficiency and reliability concerns.
Innovation Solution
A compressor design incorporating a discharge valve with a communication hole, where the hole's cross-sectional area is 5% to 10% of the discharge hole's area, positioned to coincide with the discharge hole's center, and formed in a cylindrical shape to prevent reverse flow and maintain oil level by allowing controlled backflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the compressor operates under conditions exceeding the designed compression ratio, then higher pressure output is achieved, but reverse flow of refrigerant occurs causing orbiting scroll rotation and oil level reduction
Solution Approach 1:
The discharge valve is positioned to close before the compression cycle completes, creating a preliminary barrier against reverse flow. This anticipatory action prevents refrigerant from flowing back into the compression chamber, thereby preventing orbiting scroll rotation and maintaining oil levels even when operating above designed compression ratios
Solution Approach 2:
The discharge valve acts as an intermediary component between the compression chamber and the discharge line. By controlling the timing of opening and closing, it mediates the pressure differential that would otherwise cause harmful reverse flow, allowing high pressure output while preventing detrimental backflow effects
2Reliability
If the discharge valve closes early to prevent reverse flow, then operational stability is improved, but compression efficiency may be reduced
Solution Approach 1:
The discharge valve timing is dynamically optimized to close at the precise moment when pressure differential reverses, balancing the need to prevent reverse flow with the need to maintain compression efficiency. This dynamic control allows the system to achieve operational stability without significant efficiency loss
Data Source
AI summary
A compressor comprises a discharge valve which is provided so as to be coupled to a fixed scroll and open/close a discharge hole. The discharge valve includes a coupling portion which is coupled to one surface of the fixed scroll, the surface facing a muffler, and a head portion extending from the coupling portion and opening/closing the discharge hole. The head portion may be provided with a communicating hole for allowing the discharge hole and the muffler to be in communication with each other. Accordingly, a backflow of a compressed refrigerant is prevented during the operation of the compressor, and thus over-compression of the refrigerant can be prevented. Also, when the compressor stops operating, only a certain amount of the discharged refrigerant is allowed to flow backward to prevent a reverse rotation of an orbiting scroll and a decrease in the oil level of the oil stored in a case.