Laser Fan Blade Tip Clearance Inspection Without Rotor Disassembly

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Solution Overview

Problem

Current methods for measuring fan blade tip clearance in turbines are time-consuming and labor-intensive, often requiring the removal of fan blades and spinner cones, which can be costly and disruptive, and may lead to additional inspections and repairs.

Innovation Solution

A system and method using a computer-based blade tip clearance system with a laser measuring head unit and inclinometer mounted on a bracket affixed to the fan rotor, allowing for non-invasive, rapid measurement of blade tip clearance by projecting a laser beam onto the fan casing and receiving the reflected beam to determine distances and angular positions, eliminating the need to remove blades or spinner cones.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional measurement methods are used, then measurement accuracy can be achieved, but inspection time and labor requirements increase significantly

Engineering Contradiction:

Improveblade tip clearance measurement accuracyVSAvoidinspection time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces manual mechanical measurement methods with an optical measurement system consisting of a laser beam projector and sensor. The laser beam is projected from the rotor hub through the blade tip clearance to the casing, and the sensor detects the beam position and distance, enabling non-contact measurement of clearance without requiring physical access or removal of components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a laser beam as an intermediary to transfer measurement information through the clearance space. The laser beam acts as a mediator that can traverse the clearance without physical contact, allowing the measurement system to obtain clearance dimensions by detecting the beam's interaction with the casing surface rather than requiring direct mechanical measurement.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If fan blades are removed for inspection, then measurement access is improved, but rotor balance and operational integrity are compromised

Engineering Contradiction:

Improvemeasurement accessVSAvoidrotor balance

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent substitutes mechanical access requirements with optical measurement capability. Instead of removing blades to physically access the clearance, the system uses a laser beam that can pass through the clearance space without physical contact, maintaining rotor assembly integrity while enabling measurement.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent enables the rotor assembly to serve itself by allowing the laser measurement system to access clearance information through the existing operational structure without disassembly. The rotor hub and blade tips themselves become part of the measurement pathway rather than obstacles requiring removal.

Inventive Principle:

Principle #25Self-service

3Adaptability or versatility

If multiple workers and scaffolding are used, then inspection coverage is improved, but cost and complexity increase

Engineering Contradiction:

Improveinspection coverageVSAvoidinspection setup complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent enables a single operator to perform the entire measurement procedure independently. The laser measurement system is designed to be manually positioned and operated by one person, eliminating the need for multiple workers, scaffolding, or complex support structures required by traditional measurement methods.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces complex mechanical access systems (scaffolding, multiple workers, disassembly procedures) with a lightweight optical measurement system that can be manually positioned and operated, significantly reducing the resources and complexity required for inspection.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 quick and accurate measurement of fan blade tip clearance, reducing inspection time and labor, maintaining rotor balance, and minimizing disruption and costs, while ensuring efficient fan operation and reducing wear.

Implementation Method 1

Methodology Applied

Scientific EffectLaser: Laser

Implementation Method 2

A system and method using a computer-based blade tip clearance system with a laser measuring head unit and inclinometer mounted on a bracket affixed to the fan rotor

Methodology Applied

Scientific EffectInclinometer:

Data Source

PatentEP4239282B1System and method for inspecting fan blade tip clearance relative to an abradable fan case

Publication Date: 2026.04.08 GENERAL ELECTRIC CO

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AI summary

A system (100) and method for inspecting fan blade clearances in a fan casing (210) are presented. The method includes manually installing a bracket (230) that includes a laser module (235) and an inclinometer (236) to a fan rotor (215) that when rotated projects a laser beam from the laser module (235) to the fan casing (210) to determine a distance measurement between the laser module (235) and the fan casing (210) at multiple circumferential points around the fan casing (210). The distance measurement and circumferential position data is processed by a server (110) to determine a clearance distance between a fan blade (320) and the fan casing (210).