Seal Segment Housing Extension for Leakage and Flutter Suppression
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Solution Overview
Problem
In rotating machines, shaft seal devices with multiple segment structures experience fluid flow changes and fluttering issues in thin-plate seal pieces, leading to leakage and wear.
Innovation Solution
The design incorporates a seal segment with inclined thin-plate seal pieces and a housing extending part that protrudes inward in the radial direction, reducing fluid leakage and contact between components, thereby suppressing fluttering and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shaft seal device is provided around the rotation surface with multiple segment structures, then the sealing capability is improved, but fluid leakage occurs between seal segments causing fluttering in thin-plate seal pieces
Solution Approach 1:
The housing extending part is designed to extend in the radial direction from the housing main body, creating a three-dimensional barrier that blocks fluid leakage paths between seal segments. This radial extension adds a new dimensional element to the sealing structure, effectively preventing fluid from reaching the end surfaces of the seal body and eliminating the cause of fluttering in thin-plate seal pieces
2Adaptability or versatility
If thin-plate seal pieces are used for sealing, then the flexibility and adaptability are improved, but wear occurs due to contact with fluid flow and surrounding components
Solution Approach 1:
The housing extending part serves as an intermediary protective structure between the fluid flow and the thin-plate seal pieces. By blocking the fluid path and preventing direct contact between the fluid and the seal pieces, the extending part reduces wear and extends the service life of the flexible thin-plate seal pieces while maintaining their adaptability
3Reliability
If the housing extends inward in the radial direction to suppress leakage, then the sealing performance is improved, but the rigidity of thin-plate seal pieces may increase due to contact
Solution Approach 1:
The housing extending part is designed with specific geometric characteristics including inclination angles that allow it to suppress fluid leakage while avoiding excessive contact with the thin-plate seal pieces. The extending part is inclined relative to the radial direction at angles greater than the end surfaces of the seal body, creating a localized sealing barrier that prevents fluid access without causing significant rigidity increase in the seal pieces
Data Source
AI summary
A seal segment comprises: a seal body having a plurality of thin-plate seal pieces that extend while being inclined forward in a rotational direction of a rotating shaft as the pieces draw farther inward in a radial direction of the rotating shaft, and that are layered in a circumferential direction of the rotating shaft; a pair of side plates extending in the circumferential direction so as to cover the seal body from both sides with respect to an axial direction of the rotating shaft; and a housing having a housing main body that accommodates the seal body while allowing the seal body to protrude inward in the radial direction, and an extending part that is provided to an end portion of the housing main body in the circumferential direction, and that extends inward in the radial direction along an end surface of the seal body in the circumferential direction.