Screw Compressor Slide Valve Leakage Reduction
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Solution Overview
Problem
In screw compressors with a slide valve mechanism, high-pressure refrigerant gas constantly leaks from the inflow hole into the low-pressure space, leading to performance degradation due to the pressure difference between chambers.
Innovation Solution
A screw compressor design with a slide valve movement mechanism that includes a third inflow hole positioned to be closed by the piston when it stops, preventing high-pressure refrigerant gas from flowing into the second chamber and reducing leakage by isolating the high-pressure space from the low-pressure space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the valve in the communication flow passage is opened to move the slide valve, then the slide valve can be moved to adjust the internal volume ratio, but high-pressure refrigerant gas constantly flows into the second chamber and leaks to the low-pressure space, causing performance degradation
Solution Approach 1:
The patent divides the single second chamber into multiple sub-chambers (second chamber and third chamber) separated by a partition wall. Each sub-chamber has its own inflow hole and flow passage to the low-pressure space. This segmentation allows selective opening/closing of individual flow passages, preventing constant leakage while maintaining slide valve mobility for internal volume ratio adjustment.
Solution Approach 2:
The patent introduces a movable partition wall that can dynamically separate or connect the second and third chambers based on operational requirements. This dynamic configuration allows the system to switch between different flow patterns, enabling slide valve movement while minimizing refrigerant gas leakage by closing off unnecessary flow paths.
2Ease of operation
If high-pressure refrigerant gas flows into the second chamber through the inflow hole, then the piston can be moved to drive the slide valve, but the refrigerant gas constantly flows out to the low-pressure space during valve opening, reducing compressor suction flow rate
Solution Approach 1:
The patent segments the flow paths by providing separate inflow holes and flow passages for the second and third chambers. This allows the system to open only the necessary flow passage for slide valve movement while keeping other passages closed, thereby maintaining compressor suction flow rate and preventing unnecessary refrigerant gas leakage to the low-pressure space.
Solution Approach 2:
The partition wall with selective flow passages acts as an intermediary between the high-pressure space and the low-pressure space. It controls and regulates the flow of refrigerant gas, allowing movement of the slide valve while preventing direct constant leakage, thus maintaining system productivity.
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 solution effectively reduces refrigerant gas leakage from the second chamber to the low-pressure space, enhancing the compressor's performance by maintaining a stable pressure ratio and preventing premature discharge, thus improving operational efficiency.
Implementation Method 1
The piston is moved because of the pressure difference between the first chamber and the second chamber
Implementation Method 2
the third inflow hole is located at a position at which the third inflow hole is closed by the piston when the piston lies at a stop position
Data Source
AI summary
A screw compressor has a slide valve movement mechanism that includes a cylinder provided in a casing body, a piston partitioning an interior of the cylinder into a first chamber and a second chamber, and a communication flow passage through which the second chamber communicates with a low-pressure space. The cylinder includes a first inflow hole, a second inflow hole, and a third inflow hole. The first chamber communicates with a high-pressure space through the first inflow hole, the second chamber communicates with the low-pressure space through the second inflow hole and the communication flow passage, and the second chamber communicates with the high-pressure space through the third inflow hole. The third inflow hole is located at a position at which the third inflow hole is closed by the piston when the piston lies at a stop position at which the piston moves toward the second chamber and stops.