Aft Inner Cap Plate Removal Tooling for Bound Micromixer Tubes

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Solution Overview

Problem

The aft plate in a gas turbine combustor deforms due to extreme temperatures, causing micromixer tubes to bind and requiring safe removal without damaging the fuel injectors.

Innovation Solution

A threaded rod mechanism is used to push the aft plate off the micromixer tubes, either from inside or outside the combustor, using a base plate and threaded rod to deform and separate the aft plate without damaging the tubes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the aft plate is removed by moving it to the right, then the aft plate can be removed from the combustor, but the fuel injectors may be damaged

Engineering Contradiction:

Improveaft plate removalVSAvoidfuel injector integrity

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

A threaded rod removal tool serves as an intermediary mechanism between the operator and the aft plate. The threaded rod engages with the aft plate and allows controlled removal through rotational motion, preventing direct manual contact that could damage the fuel injectors. The tool acts as a mediator that transfers force safely from the operator to the aft plate while protecting the underlying tubes.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The removal tool is prepared in advance with a threaded rod designed to engage specifically with the aft plate geometry. The base plate is pre-configured with mounting features that allow secure attachment to the combustor end cover before removal begins. This preliminary preparation ensures that when removal is needed, the proper tooling is already in place to prevent damage to the fuel injectors.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the micromixer tubes are closely fitted in the aft plate, then the fuel injection performance is improved, but the tubes may bind due to thermal stress and mechanical fatigue

Engineering Contradiction:

Improvefuel injection performanceVSAvoidthermal stress and mechanical fatigue

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The removal tool is designed with a threaded rod that can be rotated to apply controlled force to the aft plate before the tubes are fully engaged. This preliminary action allows the plate to be gradually separated from the tubes, preventing sudden binding forces from damaging the closely fitted micromixer tubes while maintaining their performance characteristics.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The removal process utilizes dynamic rotational motion of the threaded rod to progressively separate the aft plate from the micromixer tubes. The rotational action allows controlled, gradual separation rather than forced linear extraction, enabling the plate to be dynamically detached without imposing excessive binding forces on the closely fitted tubes.

Inventive Principle:

Principle #15Dynamics

3Ease of operation

If the aft plate is deformed during removal, then the plate can be separated from the tubes, but the deformation may affect the structural integrity

Engineering Contradiction:

Improveplate separationVSAvoidstructural integrity

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The threaded rod acts as an intermediary that applies controlled deformation forces to the aft plate during removal. By rotating the threaded rod, force is applied progressively to separate the plate from the tubes, allowing necessary deformation to occur through the controlled mechanism rather than uncontrolled forcing that would compromise structural integrity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The removal process changes the physical state of the aft plate from a rigid, tightly fitted condition to a deformed, separated state through controlled rotational force application. The threaded rod mechanism allows this parameter change (from fitted to separated) to occur in a controlled manner that separates the plate from the tubes while managing the structural implications through gradual deformation rather than sudden failure.

Inventive Principle:

Principle #35Parameter changes

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

Enables safe and efficient removal of the aft plate and inner cap assembly from the micromixer tubes, preventing damage to the fuel injectors during maintenance.

Implementation Method 1

rotation of the threaded rod to deform the aft plate

Methodology Applied

Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

the threaded rod pushes the aft plate off of the tubes

Methodology Applied

Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentUS12434362B2Aft inner cap plate removal method and tooling for a combustor with micromixer tubes

Publication Date: 2025.10.07 GE INFRASTRUCTURE TECH LLC

AI summary

The present application provides an aft plate removal tool for servicing a combustor. The combustor includes an end cover, an aft plate downstream of the end cover, and a number of tubes extending through the aft plate. The aft plate removal tool includes a base plate and a threaded rod. The base plate is attached to the end cover. Rotation of the threaded rod advances the threaded rod against the aft plate until the threaded rod pushes the aft plate off of the tubes.