Seal Assembly Anti-Rotation Lock for Axial Sealing Stability

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Solution Overview

Problem

Existing seal assemblies in gas turbine engines face challenges in preventing the rotation of seal elements, which can lead to wear and degradation of stationary components due to frictional forces, necessitating an improved solution to maintain effective sealing and prevent rotation.

Innovation Solution

The proposed solution involves a seal assembly with a rotating structure, a stationary structure, and an anti-rotation lock that projects radially into the seal element, preventing its rotation relative to the stationary structure, while also allowing axial movement, using features like keys and pins to secure the seal elements in place.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If seal elements are allowed to rotate with the rotating structure, then sealing contact with the seal land is maintained, but wear and degradation of stationary components occurs due to frictional forces

Engineering Contradiction:
Improvesealing effectivenessVSAvoidwear on stationary components
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The seal element is divided into two functional parts: a rotating sealing portion that contacts the seal land to maintain sealing, and a stationary portion prevented from rotating by the anti-rotation lock mechanism. This segmentation allows the seal to perform its sealing function while preventing the harmful rotation that causes wear on stationary components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The anti-rotation lock acts as an intermediary mechanism between the rotating seal element and the stationary structure. It selectively permits rotational movement at the sealing interface while preventing rotation at the stationary component interface, thereby mediating between the need for rotational sealing and the need to prevent wear.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If seal elements are prevented from rotating, then wear on stationary components is reduced, but axial movement capability may be restricted

Engineering Contradiction:
Improvewear on stationary componentsVSAvoidaxial movement capability
Core Design Contradiction:
Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The anti-rotation lock mechanism is designed with dynamic characteristics that allow it to adapt to different operational requirements. The spring element provides flexible engagement that permits axial movement while maintaining prevention of rotation, allowing the system to adapt between maintaining seal pressure and accommodating thermal expansion or misalignment.

Inventive Principle:
Principle #15Dynamics

3Object-affected harmful factors

If anti-rotation locks are added to seal assemblies, then rotation prevention is achieved, but device complexity increases

Engineering Contradiction:
Improverotation of seal elementsVSAvoidseal assembly structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The anti-rotation lock functionality is merged with the existing seal element structure rather than being a completely separate component. The lock features are integrated into the seal element and stationary structure, combining multiple functions (sealing, anti-rotation, axial compliance) into a unified assembly that minimizes overall complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The anti-rotation lock mechanism serves multiple functions simultaneously: preventing rotation of the seal element, maintaining axial seal pressure through spring engagement, and accommodating thermal expansion or misalignment. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3795869A1Seal assembly with Anti-rotation lock
Publication Date: 2021.03.24 RTX CORP
  • EP3795869A1 patent drawingFigure 1
  • EP3795869A1 patent drawingFigure 2
  • EP3795869A1 patent drawingFigure 3~4

AI summary

An assembly is provided for rotational equipment. This assembly includes a stationary structure (24), a rotating structure (26), a seal element (68) and an anti-rotation lock (72). The rotating structure (26) is rotatable about an axis (22). The rotating structure (26) is configured as or otherwise includes a seal land (34). The seal element (68) is configured to seal a gap between the stationary structure (24) and the seal land (34). The seal element (68) extends circumferentially about the axis (22). The seal element (68) axially contacts the seal land (34). The anti-rotation lock (72) projects radially into the stationary structure (24) and the seal element (68). The anti-rotation lock (72) is configured to at least substantially prevent rotation of the seal element (68) relative to the stationary structure (24).