Abradable Seal Ring Activation via Intermediary Pressing Force
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In steam turbines, abradable seal rings with varying activation pressures face challenges in activation due to friction with the housing, particularly for high load activation rings, which may not activate as intended, leading to inconsistent and potentially incomplete sealing.
Innovation Solution
A clearance-control-type seal structure featuring arc-shaped grooves and seal rings with extended parts that overlap radially, allowing the second seal ring to assist in activating the first seal ring by applying a pressing force, ensuring secure activation of each abradable seal ring at the desired time, even under high load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If abradable seal rings with different activation pressures are used, then the sealing performance is optimized for different operational stages, but the high load activation seal ring may not activate due to friction with the housing
Solution Approach 1:
The patent introduces an intermediary mechanism (the pressing structure of the second extended part) that mediates between the back pressure force and the first seal ring. This intermediary applies additional radial pressing force to overcome friction directly at the interface, ensuring reliable activation without requiring higher back pressure that would compromise sealing performance.
Solution Approach 2:
The second seal ring's extended part is designed to press the first seal ring toward the groove wall before the back pressure fully activates the first seal ring. This preliminary action reduces the activation threshold by pre-overcoming the static friction, allowing the first seal ring to activate reliably at the intended operational stage.
2Reliability
If the second extended part presses the first extended part, then activation reliability is improved, but the structural complexity increases
Solution Approach 1:
The patent merges the activation function into the existing seal ring structure by making the second extended part itself the pressing mechanism. Rather than adding a separate actuator or complex mechanism, the design combines the sealing function with the activation assistance function in a single integrated structure.
Solution Approach 2:
The second seal ring's extended part automatically presses the first seal ring as part of its own activation process. The back pressure that activates the second seal ring simultaneously provides the pressing force needed for the first seal ring, creating a self-service mechanism that reduces complexity while improving reliability.
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 ensures consistent and secure activation of each abradable seal ring, minimizing friction-related issues and maintaining optimal sealing performance across different operational stages, including startup and rated operation.
Implementation Method 1
receives force to move inside in the radial direction from the back pressure in the grooves
Implementation Method 2
there are cases in which it may not activate due to friction with the housing
Data Source
AI summary
A clearance-control-type seal structure including a plurality of arc-shaped grooves (23) formed side by side in the axial direction with respect to an inner circumferential surface of a housing (22) of a turbine; and abradable seal rings (11, 12) having fitting parts (11a, 12a) that are fitted into the grooves so as to leave a prescribed gap, that have extended parts (11b, 12b) that are exposed from the housing in the radial direction toward the inside and expand in the axial direction, and that, during operation, due to back pressure inside the grooves, receive a force that moves in the radial direction toward the inside. One extended part has a protruding part extending even further in the axial direction toward the upstream side, and the other extended part has formed in an outer circumferential surface of a downstream-side end part thereof a recessed part that corresponds to the protruding part.