Hydrogen Generator Seal Eccentricity Management
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Solution Overview
Problem
Existing seal devices for hydrogen-cooled generators fail to effectively manage eccentricity and vibrations of the rotary shaft, leading to potential leakage of hydrogen gas and increased power generation costs due to inefficient sealing and increased frictional heat.
Innovation Solution
The seal device features circumferentially divided seal rings on one end and a unified seal ring on the other, supported by a bearing pedestal independent of the casing, with a low-rigidity material layer on the seal casing, to enhance the follow-up of rotary shaft eccentricity and reduce vibrations by increasing the oil film rigidity and minimizing seal oil flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a unified seal ring is used on both ends of the rotary shaft, then the sealing structure is simple, but the seal cannot effectively follow the eccentricity of the rotary shaft, leading to hydrogen gas leakage
Solution Approach 1:
The seal ring on one end of the rotary shaft is divided into multiple circumferential segments that can independently move radially to follow the eccentricity of the rotary shaft. This segmentation allows each segment to adapt to the varying clearance caused by shaft eccentricity, maintaining effective sealing without requiring a complex overall structure.
2Stress or pressure
If the seal ring is made rigid to maintain sealing pressure, then the sealing pressure is stable, but the seal ring cannot follow the eccentricity of the rotary shaft, causing leakage
Solution Approach 1:
The seal ring segments are designed with dynamic characteristics, allowing them to move radially in response to the eccentricity of the rotary shaft while maintaining contact pressure. The segments can dynamically adjust their position to follow the shaft center movement, ensuring continuous sealing effectiveness under varying operating conditions.
3Device complexity
If the bearing is supported by the casing to simplify the structure, then the structure is compact, but the seal device cannot effectively follow the rotary shaft eccentricity
Solution Approach 1:
The bearing support structure is segmented into an independent bearing pedestal separate from the casing. This allows the bearing and seal device to move independently relative to the casing, enabling the seal to follow the rotary shaft eccentricity while maintaining a relatively simple overall structure.
4Temperature
If the seal ring contact area with the rotary shaft is reduced, then the frictional heat is reduced, but the sealing effectiveness is compromised
Solution Approach 1:
The seal ring segments have different contact characteristics with the rotary shaft. The segments experience varying degrees of contact and friction depending on their position relative to the shaft eccentricity. This local variation in contact quality allows the seal to maintain effectiveness at critical locations while minimizing overall frictional heat generation.
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 configuration effectively reduces vibrations and hydrogen gas leakage by improving the seal's ability to follow the rotary shaft's eccentricity, maintaining the hydrogen gas pressure and cooling efficiency, thus minimizing the need for hydrogen replenishment and reducing power generation costs.
Implementation Method 1
providing a low rigidity material layer on the seal casing or seal ring where the casing is in contact with the seal ring
Implementation Method 2
increasing the pressure of oil that is supplied to a clearance between the surface of the rotary shaft and the surface of the seal ring
Data Source
AI summary
The seal devices on both ends of the rotary shaft are supported by the casing, the bearing on one end of the rotary shaft is supported by a bearing pedestal which is separated of the casing, the bearing on the other end of the rotary shaft is supported by the casing, the seal ring of the seal device on one end of the rotary shaft is divided into circumferential segments, and the seal ring of the seal device on the other end of the shaft is a unified seal ring.