Closed Impeller Compressor Layout to Prevent Surge Shaft Bending
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Solution Overview
Problem
In existing centrifugal compressors, the radial bearing is positioned closer to the center than the impeller, leading to shaft bending during surges, which can result in damage to components like the radial bearing.
Innovation Solution
A centrifugal compressor design where the first bearing supporting the impeller is placed outside the radial direction of a cover member, which covers the impeller's end portion, allowing it to support radial loads and prevent shaft bending during surges, with the option of using a gas bearing for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the radial bearing is positioned closer to the center than the impeller, then the bearing can support the rotation shaft, but the shaft bends during surges causing component damage
Solution Approach 1:
The patent moves the radial bearing from an axial position (closer to center) to a radial position (outside the cover member). This dimensional change in bearing placement allows the bearing to directly support radial loads on the impeller, preventing shaft bending during surge conditions while maintaining rotational support functionality.
2Productivity
If the impeller is configured as closed with cover member, then operational efficiency increases, but device complexity increases
Solution Approach 1:
The patent merges the cover member with the impeller structure to form a closed impeller configuration. This integration combines the functions of the impeller blades and the cover into a unified structure, improving operational efficiency by eliminating leakage paths while the bearing placement outside the cover manages the added structural complexity.
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
This design effectively suppresses shaft bending during surges, reduces the risk of damage to other components, and improves operational efficiency by using a closed impeller configuration and high-speed rotation capabilities of gas bearings.
Implementation Method 1
the first bearing (15) is a gas bearing
Data Source
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AI summary
A centrifugal compressor includes: a shaft member (52) that extends in an axial direction and that is rotatable; and an impeller (12) including a hub (121) that is disposed on an end portion of the shaft member (52) and a plurality of blades (122, 123) that are disposed on an outer peripheral surface of the hub (121). The impeller (12) has a shape that tapers outward in the axial direction. A cover member (125) is disposed at least at an end portion (12a) of the impeller (12) outside in the axial direction, the cover member (125) being joined to outer peripheries of the plurality of blades (122, 123) in a radial direction and covering at least a part of the plurality of blades (122, 123) from outside in the radial direction. A first bearing (15) that rotatably supports the impeller (12) is disposed outside in the radial direction of the cover member (125).