Seal Segment Structure to Suppress Thin Plate Fluttering
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Solution Overview
Problem
The existing shaft seal devices in rotary machines face challenges in restricting the flow of thin plate seal pieces to small gaps, leading to deterioration in floating performance and fluttering of these pieces.
Innovation Solution
A seal segment design that includes a retainer extending circumferentially and a seal body with laminated thin plate seal pieces, where high-pressure and low-pressure plates are sandwiched between the seal body and retainer, and a block body with simulation sections to enhance resistance to fluttering and maintain floating characteristics, along with a contact seal for conformability and an elastic member for adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separate high-pressure side plate and low-pressure side plate are used, then the structure is simple and easy to manufacture, but the flow restriction capability deteriorates and fluttering occurs
Solution Approach 1:
The patent merges the high-pressure side plate and low-pressure side plate into a single integrated plate structure. This integrated plate simultaneously performs both high-pressure sealing and low-pressure sealing functions, eliminating the fluttering issue caused by separate plates while maintaining manufacturing simplicity. The merged structure ensures stable floating performance of the thin plate seal pieces.
2Reliability
If thin plate seal pieces are made thinner, then the floating characteristics improve, but the resistance to fluttering deteriorates
Solution Approach 1:
The patent applies local quality by making the thin plate seal pieces thinner only in the sealing contact region to improve floating characteristics, while providing structural support and rigidity in the non-contact regions through the integrated plate design. This localized thinning maintains sealing performance while preventing fluttering in areas where it would be harmful.
3Strength
If the seal body is made more rigid, then the resistance to fluttering increases, but the conformability to axial deviation deteriorates
Solution Approach 1:
The patent employs dynamics by designing the thin plate seal pieces with controlled flexibility that allows them to dynamically adapt to axial deviations of the rotor while the integrated plate structure provides overall rigidity to prevent fluttering. The system transitions between flexible sealing contact and rigid structural support based on operational conditions.
Data Source
AI summary
A seal segment (11) includes a retainer (21), a seal body (13) having a thin plate seal piece (20), a high-pressure side plate (23), a low-pressure side plate, a retainer simulating section (51) further extending in the circumferential direction (Dc) from an end portion of the retainer (21) in the circumferential direction (Dc), and a block body (50) including a seal body simulation section (53) extending inward in the radial direction (Dr) from the retainer simulation section. The high-pressure side plate (23) and the low-pressure side plate cover at least a part of the seal body simulation section (53) of the block body (50).