Compressor interstage throttle, and method of operating therof
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Solution Overview
Problem
Centrifugal compressors in HVACR systems face challenges in efficiently managing the flow rate of working fluid between stages, leading to suboptimal pressure increase and energy efficiency due to the lack of precise control over the interstage throttle mechanism.
Innovation Solution
An interstage throttle system comprising a flow guide plate with radially inward channels, a throttle ring with teeth, and linkage assemblies connecting the drive ring to the throttle ring, allowing axial movement between retracted and extended positions to adjust the channel blockage, thereby controlling the flow rate and pressure increase between stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a centrifugal compressor uses multiple stages to compress working fluid, then the pressure increase capability is improved, but the control over flow rate between stages becomes complex and less efficient
Solution Approach 1:
The patent applies the dynamics principle by making the throttle ring movable along the axial direction rather than fixed. The throttle ring can dynamically adjust its position to change the degree of blockage in the channels, allowing real-time control of flow rate between compressor stages. This dynamic adjustment mechanism resolves the contradiction by providing flexible flow control without requiring complex multi-component systems.
Solution Approach 2:
The patent segments the flow control function into distinct components: the flow guide plate with channels, the throttle ring with teeth, and the linkage assembly. This segmentation allows each component to perform a specific function - the channels guide flow, the throttle ring blocks flow, and the linkage translates rotational motion to axial movement. This modular approach simplifies the overall control system while maintaining effective flow rate management between stages.
2Device complexity
If the interstage throttle mechanism lacks precise control, then the structure remains simple, but the energy efficiency and operational capacity deteriorate
Solution Approach 1:
The patent incorporates feedback through the linkage assembly that connects the drive ring to the throttle ring. The linkage mechanism provides a mechanical feedback system where rotational position of the drive ring directly corresponds to the axial position of the throttle ring, enabling precise and repeatable flow control. This feedback mechanism allows the system to maintain optimal energy efficiency by precisely controlling flow rate without requiring complex electronic control systems.
Solution Approach 2:
The patent changes the positional parameter of the throttle ring along the axial direction to control flow rate. By varying the axial position of the throttle ring, the degree of channel blockage is changed, which directly controls the flow rate between stages. This parameter change approach enables precise flow control and optimizes energy efficiency while maintaining relatively simple mechanical structure.
3Measurement precision
If the throttle ring is positioned in the extended position to block channels, then the flow rate control precision is improved, but the axial space requirement increases
Solution Approach 1:
The patent applies the nesting principle by positioning the throttle ring within the existing axial space of the compressor housing, nesting it among other components. The throttle ring operates within the available axial gap between the flow guide plate and the housing, utilizing unused space efficiently. This nesting approach allows the throttle mechanism to achieve precise flow control without significantly increasing the overall axial length of the compressor.
Data Source
AI summary
An interstage throttle for a centrifugal compressor includes a flow guide plate, a throttle ring, a drive ring, and linkage assemblies. The flow guide plate includes guide vanes that form channels that direct working fluid in between stages of the compressor. The linkage assemblies connect the drive ring to the throttle ring such that rotation of the drive ring moves the throttle ring in an axial direction. Teeth of the throttle ring partially block the channels when the throttle ring is in an extended position. A method of operating a centrifugal compressor includes directing the working fluid discharged from the first stage to a second stage via channels in a interstage throttle. A centrifugal compressor includes a first stage with a first impeller, a second stage with a second impeller, and an interstage throttle fluidly connecting the first stage to the second stage.