Semi-Annular Counter Weight for Turbine Casing Removal

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Solution Overview

Problem

The removal and reinstallation of the lower half of the inner turbine casing in gas turbine engines pose challenges due to limited workspace and tight tolerances, risking damage to components during maintenance.

Innovation Solution

A semi-annular counter weight system with a radial gear rack and drive system allows for the rotation and removal of the lower inner casing portion, providing access for maintenance without full disassembly, using a counter weight with a semi-annular main body and radial gear rack segments for alignment and support.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the lower half of the inner turbine casing is removed for complete inspection, then access to all turbine components is improved, but the risk of damage to turbine components increases due to tight tolerances and limited workspace

Engineering Contradiction:
ImproveAccess to turbine componentsVSAvoidRisk of component damage
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The inner turbine casing is divided into an upper half and a lower half that can be separated from each other. The lower half can be independently removed while the upper half remains in place, allowing access to turbine components without complete disassembly. This segmentation enables maintenance personnel to access the turbine rotor and other components while maintaining structural support and reducing damage risk.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A specialized removal tool or mechanism acts as an intermediary between the lower half casing and the turbine components. This intermediary device facilitates the removal and reinstallation processes by providing controlled support and alignment, thereby minimizing the risk of damage to the turbine components during the maintenance operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If mechanical jacks are used to support the lower half casing, then proper alignment is improved, but the complexity of the support system increases

Engineering Contradiction:
ImproveCasing alignmentVSAvoidSupport system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The support system is designed to provide uniform support at multiple points around the lower half casing, creating an equipotential support condition that maintains proper alignment without requiring complex adjustment mechanisms. The support points are positioned to distribute the load evenly and maintain the casing's natural alignment position.

Inventive Principle:
Principle #12Equipotentiality

3Ease of operation

If the entire turbine rotor is removed for maintenance, then complete access to all components is achieved, but the downtime and complexity of maintenance increase

Engineering Contradiction:
ImproveComponent accessibilityVSAvoidMaintenance downtime
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The turbine casing is segmented into removable sections (upper and lower halves) that can be independently accessed. This allows maintenance personnel to remove only the necessary section to access specific components, rather than removing the entire rotor assembly. Consequently, maintenance can be performed more quickly with reduced downtime while still achieving complete access to all turbine components.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2730753B1A system for assembling and disassembling a turbine section of a gas turbine
Publication Date: 2015.09.02 GENERAL ELECTRIC CO
  • EP2730753B1 patent drawingFigure 1
  • EP2730753B1 patent drawingFigure 2
  • EP2730753B1 patent drawingFigure 3

AI summary

A counter weight (62) for installing and removing a lower portion of an inner casing of a turbine section generally includes a semi-annular main body (72) having a first radially extending mating surface (84) and a second radially extending mating surface (86). A radial gear rack (90) extends radially outward from the main body. The radial gear rack (90) includes a primary segment that extends a first angular distance between the first radially extending mating surface (84) and the second radially extending mating surface (86) of the main body (72). A secondary segment of the radial gear rack (90) extends a second angular distance from the second radially extending mating surface (86) of the main body (72). The secondary segment defines an at least partially linear inner surface and an outer arcuate surface.