Precision-Milled Impeller Design for Centrifugal Compressor
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Solution Overview
Problem
Prior impeller designs, such as those used in centrifugal compressors, suffer from 'slop' and limited output due to molding processes, lack of precision, and structural integration issues, leading to residual stresses and fatigue fractures, especially in high-speed applications.
Innovation Solution
A precision-milled impeller design featuring a cover member, hub member, and blades formed from a single metal-based material, with a hub enclosure ring attached to enhance structural integrity and minimize failure points, eliminating the need for brazing and its associated issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If impellers are formed by molding processes, then manufacturing efficiency is improved, but manufacturing precision and structural integrity deteriorate
Solution Approach 1:
The patent replaces the molding process with a machining process. Specifically, the impeller is formed by machining operations (milling, turning, drilling) rather than molding, which allows for much higher precision and structural integrity while maintaining manufacturing efficiency through automated CNC machining centers.
2Strength
If impellers are formed as monolithic structures, then structural integrity is improved, but manufacturing complexity and residual stress increase
Solution Approach 1:
The impeller is divided into multiple separate components (impeller body, hub, cover) that are machined independently and then assembled. This segmentation reduces the complexity of machining each individual part, allows for stress relief between components, and eliminates the residual stresses that would occur in a single monolithic structure while maintaining overall structural integrity through precision assembly.
3Productivity
If blades are designed with complex geometries, then performance is improved, but manufacturing precision and stability deteriorate
Solution Approach 1:
Complex blade geometries are achieved through precision CNC machining operations rather than molding. The use of computer-controlled milling and turning operations allows for the creation of intricate blade shapes with high precision and stability, overcoming the limitations of molding processes which cannot accurately form complex five-axis blade designs.
4Adaptability or versatility
If multiple components are assembled, then manufacturing flexibility is improved, but assembly complexity and potential failure points increase
Solution Approach 1:
The impeller is segmented into multiple components (impeller body, hub, cover) that can be independently machined and then assembled. This segmentation provides manufacturing flexibility to optimize each component separately while the standardized interface design minimizes assembly complexity. The separate components allow for easier inspection, repair, and replacement without affecting the entire impeller assembly.
Data Source
AI summary
An impeller including a plurality of longitudinally-extending blades, each having a first edge and a second edge, a cover member with an inlet orifice and extending along at least a portion of the first edge of each of the plurality of blades, and a hub member extending adjacently along only a portion of the second edge of each of the blades. The cover member, plurality of blades and hub member are milled from a single, metal-based material of construction to form an integral, uniform structure. A kit for an impeller assembly and a method of manufacturing an impeller are also disclosed.