Steam Turbine Rotor Seal Key Member Design
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Solution Overview
Problem
Conventional approaches for retaining circumferential seals in steam turbines allow for unwanted rotation, slipping, and creep, which diminishes seal effectiveness and causes wear on components.
Innovation Solution
A rotor key member with a main body, first and second arms defining an axial space, and a hook extending to contact the radially inner surface of the seal, providing radial retention and preventing rotation, made from a deformable material with optional apertures for weight reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional approaches are used for retaining circumferential seals, then the seal can be installed, but unwanted rotation, slipping, and creep occur which diminish seal effectiveness
Solution Approach 1:
The key member incorporates a deformable material that allows dynamic adaptation to the seal and rotor surface. The key member can deform during installation to accommodate variations in the rotor surface and seal geometry, then maintains a stable engaged position during operation, preventing rotation and slipping while ensuring consistent sealing contact.
Solution Approach 2:
The patent utilizes the deformable property of the key member material as a changing parameter during installation and operation. The key member transitions from a deformable state during installation to a stable engaged state during operation, allowing it to adapt to surface variations and maintain optimal sealing contact under varying operational conditions.
2Reliability
If a rigid key member is used, then structural strength is maintained, but it cannot adapt to surface variations causing inconsistent sealing
Solution Approach 1:
The patent utilizes the deformable property of the key member material as a changing parameter during installation and operation. The key member transitions from a deformable state during installation to a stable engaged state during operation, allowing it to adapt to surface variations and maintain optimal sealing contact under varying operational conditions.
Solution Approach 2:
The key member is made from a deformable material that combines adaptability with sufficient structural strength. This deformable material allows the key member to conform to surface variations for consistent sealing while maintaining the strength necessary to prevent rotation and slipping under operational loads.
3Ease of manufacture
If the key member structure is simplified, then manufacturing is easier, but it cannot provide both radial retention and rotation control
Solution Approach 1:
The key member is designed as a multi-functional component that simultaneously provides radial retention through its engagement with the rotor surface, rotation control through its hooked configuration, and sealing support by maintaining contact with the seal. This universal design consolidates multiple retention functions into a single deformable component, simplifying the overall structure while ensuring comprehensive seal retention.
Data Source
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AI summary
The invention is related to a rotor key member (20), along with a related steam turbine rotor assembly assembly (22). The rotor key member (20) for retaining a circumferential seal (24) includes a main body (26), a first arm (28) extending from the main body (26), a second arm (30) extending from the main body (26), wherein the first arm (28), the second arm (30) and the main body (26) define a space (32) spanning axially (A) between the first arm (28) and the second arm (30) and a hook (34) extending from the second arm (30) in a direction axially away from the space, the hook (34) sized to contact a radially inner surface (36) of the circumferential seal (24). With the above configuration the rotor key member (20) restrains the cirumferential seal (24) in a slot (48) in the rotor body (46) of a steam turbine rotor.