Centrifugal Compressor Adjusting Mechanism for Surge Prevention
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Solution Overview
Problem
Conventional centrifugal chillers face challenges in efficiently adjusting capacity to respond to load variations, primarily relying on rotating speed and inlet guide vane control, which limits their operational flexibility and stability.
Innovation Solution
An adjusting mechanism for a centrifugal compressor that includes a diffuser channel width adjusting assembly and a gas bypass assembly, allowing for simultaneous adjustment of the diffuser channel width and gas bypass port opening through a drive shaft and valve stems, expanding the operating envelope and preventing surge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional capacity control methods (rotating speed and inlet guide vane adjustment) are used, then the chiller can respond to load variations, but the operational flexibility and stability are limited
Solution Approach 1:
The patent makes the diffuser channel width adjustable through a valve stem and annular plate mechanism, transforming a static component into a dynamic one. This allows the diffuser channel width to be varied during operation, expanding the compressor's operating range and improving adaptability to different load conditions while maintaining stable operation.
Solution Approach 2:
The invention changes the geometric parameter of the diffuser channel width to control compressor performance. By adjusting the width of the diffuser channel, the system can optimize flow characteristics and prevent surge at reduced refrigerant mass flow rates, thereby improving both operational flexibility and stability simultaneously.
2Reliability
If the diffuser channel width is adjusted to expand the operating envelope, then the compressor can operate stably at reduced flow rates, but the device complexity increases
Solution Approach 1:
The valve stem and annular plate mechanism serves multiple functions: it adjusts the diffuser channel width, controls the gas bypass port opening, and maintains sealing between the movable components. This multi-functionality reduces the need for separate mechanisms, thereby limiting the increase in device complexity while achieving stable operation at reduced flow rates.
Solution Approach 2:
The annular plate is movably disposed within the diffuser passage, and the valve stem passes through the annular plate to drive it. This nested arrangement allows compact integration of multiple components in a space-efficient manner, minimizing the increase in device complexity while enabling diffuser width adjustment for stable reduced-flow operation.
3Adaptability or versatility
If gas bypass assembly is added to control surge, then the operating envelope is expanded, but the piping costs increase
Solution Approach 1:
The gas bypass valve is integrated into the existing compressor structure, with the valve stem sharing the same drive shaft as the diffuser adjusting mechanism. The bypass passage is incorporated within the compressor housing rather than requiring external piping, thereby expanding the operating envelope while minimizing additional piping costs.
Solution Approach 2:
The gas bypass valve acts as an intermediary mechanism that redirects excess gas back to the suction side, preventing surge conditions. By using this internal bypass mechanism driven by the valve stem, the system expands its operating envelope without requiring complex external piping systems.
Data Source
AI summary
An adjusting mechanism, adaptive to a main body of a centrifugal compressor, comprises a diffuser channel width adjusting assembly and a gas bypass assembly. The diffuser channel width adjusting assembly comprises a width adjusting annular plate and a first valve stem. The width adjusting annular plate is movably disposed in a diffuser channel of the main body. The first valve stem is connected to the width adjusting annular plate, and configured for driving the width adjusting annular plate to move to adjust the width of the diffuser channel. The gas bypass assembly comprises a gas bypass valve and a second valve stem. The gas bypass valve is movably disposed in a gas bypass passage of the main body. The second valve stem is connected to the gas bypass valve, and configured for driving the gas bypass valve to move to adjust the opening of the gas bypass port.