Retractable Seal Segment with Bypass Passage for Turbine Sealing
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Solution Overview
Problem
Current seal systems in rotary machines, such as steam turbines and gas turbines, face issues with seal degradation due to transient events and rotor vibrations, leading to rubbing and inefficient leakage control, as they rely on passive methods that do not maintain a minimum seal distance during varying load and thermal conditions.
Innovation Solution
A retractable seal segment with a bypass passage that creates a pressure cushion as the seal closes, allowing for self-adjustable minimum seal gap control through fluid flow, eliminating the need for mechanical actuators and external pressure systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive seal segments are used, then the structure is simple, but the seal distance cannot be maintained during transient events and rotor vibrations
Solution Approach 1:
The seal segment incorporates a bypass passage that allows fluid to flow through it, creating a pressure cushion that automatically pushes the seal segment away from the rotor surface. This self-regulating mechanism maintains a minimum seal distance during transient events and vibrations without requiring external actuators or complex control systems.
Solution Approach 2:
The invention utilizes fluid pressure generated through the bypass passage to create a pneumatic cushion between the seal segment and the rotor. This hydraulic/pneumatic mechanism provides active seal positioning during transient conditions, resolving the contradiction between simple structure and reliable seal distance maintenance.
2Reliability
If active controlled seal positioning is implemented, then minimum seal distance is maintained, but the system complexity increases with actuators and external pressure systems
Solution Approach 1:
The seal segment incorporates a bypass passage that allows fluid to flow through it, creating a pressure cushion that automatically pushes the seal segment away from the rotor surface. This self-regulating mechanism maintains a minimum seal distance during transient events and vibrations without requiring external actuators or complex control systems.
Solution Approach 2:
The invention replaces complex mechanical actuator systems with a fluid-pressure-based self-regulating mechanism. The bypass passage utilizes fluid flow to generate the necessary pressure cushion, substituting mechanical complexity with a simpler hydraulic/pneumatic solution that achieves active seal positioning.
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 solution ensures a consistent minimum seal distance is maintained across different operating conditions, reducing the risk of rubbing and improving leakage control without the complexity of actuators or external pressure systems, enhancing the reliability and efficiency of the seal system.
Implementation Method 1
A retractable seal segment with a bypass passage that creates a pressure cushion as the seal closes
Implementation Method 2
allowing for self-adjustable minimum seal gap control through fluid flow
Data Source
Figure 1
AI summary
The invention relates to a sealing segment (20) for sealing between a stationary component (10) and a rotating component (15). The sealing segment (20) having a passage (30) that extends so as to enable pressure balancing between radial ends of the sealing segment (20) so by providing a seal that can ensure a minimum seal distance is maintained without the need for the complexities of actuators or other mechanical devices.