Variable Focus Optical Inspection for Turbine Component Repair

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Solution Overview

Problem

Conventional optical inspection systems for power generation apparatus components, such as gas turbine engines, face challenges with fixed focal planes, leading to out-of-focus features and reduced accuracy during inspection and repair, requiring disassembly and increasing downtime and costs.

Innovation Solution

A system with a variable focal length structure and controller to adjust the focal plane, allowing for in-situ inspection and repair by ensuring at least one region of interest is in focus without moving the system or component, using an acoustically tunable lens capable of high-temperature operation and microsecond focal plane adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a fixed focal plane optical inspection system is used, then the system structure is simple, but the inspection accuracy is reduced when features fall outside the fixed focal plane

Engineering Contradiction:
Improveinspection accuracyVSAvoidoptical system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by transitioning from a fixed focal plane optical system to a variable focal length optical system. The optical inspection system dynamically adjusts its focal length to match different distances of features of interest from the optical detector, ensuring that features at varying depths remain in focus. This dynamic adjustment capability resolves the contradiction by maintaining inspection accuracy across different feature positions while managing system complexity through controlled adaptability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs parameter changes by modifying the focal length parameter of the optical system. Instead of maintaining a constant focal plane, the system varies the focal length parameter to accommodate features at different distances from the optical detector. This parameter adjustment ensures that the optical system can focus on features of interest regardless of their position, thereby improving inspection accuracy without requiring complete system redesign.

Inventive Principle:
Principle #35Parameter changes

2Ease of repair

If components are removed for repair, then repair access is improved, but downtime and servicing costs increase

Engineering Contradiction:
Improverepair accessibilityVSAvoidapparatus downtime
Core Design Contradiction:
Ease of repairVSLoss of time

Solution Approach 1:

The patent applies the self-service principle by enabling repair operations to be performed in-situ within the gas path of the power generation apparatus. The optical repair system allows defects to be treated without removing components from the apparatus, as the repair tools and optical systems can access and treat features directly where they are located. This eliminates the need for disassembly and reassembly operations, significantly reducing downtime while maintaining ease of repair through direct access capabilities.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If the optical system position is adjusted to maintain focus, then inspection accuracy is maintained, but system complexity and operation difficulty increase

Engineering Contradiction:
Improvefocus accuracyVSAvoidsystem operation simplicity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent applies the dynamics principle by making the focal length of the optical system dynamically adjustable rather than fixed. Instead of requiring physical movement or repositioning of the optical system to maintain focus on features at different distances, the focal length parameter itself is dynamically changed. This approach maintains focus accuracy while simplifying operation, as the system can electronically or mechanically adjust focal length without complex positioning mechanisms or manual intervention.

Inventive Principle:
Principle #15Dynamics

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 solution provides a robust, cost-effective method for accurate in-situ inspection and repair, improving uptime and reducing downtime and servicing costs by maintaining focus without adjusting the system's position, and allowing for rapid focal plane variation.

Implementation Method 1

The variable focal length structure has a focal plane that is adjustable. The controller is configured to control the variable focal length structure to adjust the focal plane of the variable focal length structure, such that at least one region of interest of the component is in focus.

Methodology Applied
Scientific EffectOptical focusing: Focusing

Implementation Method 2

The variable focal length structure may include an acoustically tunable lens. The variable focal length structure may allow variation in the focal planes on a microsecond scale.

Methodology Applied
Scientific EffectAcousto-optic effect: Acousto-optic Effect

Data Source

PatentEP4283374A1System for use with component of power generation apparatus
Publication Date: 2023.11.29 ROLLS ROYCE PLC
  • EP4283374A1 patent drawingFigure 1
  • EP4283374A1 patent drawingFigure 2
  • EP4283374A1 patent drawingFigure 3

AI summary

A system (200, 600) for use with a component (102) of a power generation apparatus (10) includes a lens arrangement (202, 602) disposed proximal to the component (102). The system (200, 600) further includes a variable focal length structure (204, 604) spaced apart from the lens arrangement (202, 602) and optically coupled with the lens arrangement (202, 602). The variable focal length structure (204, 604) has a focal plane (F) that is adjustable. The system (200, 600) further includes a controller (206, 606) communicably coupled with the variable focal length structure (204, 604). The controller (206, 606) is configured to control the variable focal length structure (204, 604) to adjust the focal plane (F) of the variable focal length structure (204, 604), such that at least one region of interest (106) of the component (102) is in focus.