Optical Clearance Measurement in Rotary Machine Casings

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Solution Overview

Problem

Existing methods for measuring clearance between rotor and stator components in rotary machines, such as compressors, are inaccurate and inefficient due to the need for radial bore installation, which creates leak paths and complicates calibration, and do not effectively monitor changes in clearance caused by thermal expansion, vibrations, or out-of-round conditions.

Innovation Solution

A light-based measurement system using secant-oriented sensors and light sources disposed within internal tracks of the casing, which transmit light across the rotor blades to detect interruptions and calculate clearance, roundness, and vibrations, reducing the need for radial bores and enhancing measurement accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If radial bore installation is used for sensor mounting, then sensor installation is simplified, but leak paths are created and measurement accuracy deteriorates

Engineering Contradiction:

Improvesensor installationVSAvoidleak path prevention

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces mechanical radial bore installation with an optical measurement system that uses light sources and sensors positioned on the compressor casing to measure blade tip clearance through optical paths, eliminating the need for radial bores and associated leak paths while maintaining measurement capability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces light as an intermediary medium to transmit measurement information from the rotating blade tips to stationary sensors without requiring physical penetration of the casing, thereby avoiding leak paths while enabling clearance measurement

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If radial bore installation is used for sensor mounting, then sensor installation is simplified, but calibration complexity increases

Engineering Contradiction:

Improvesensor installationVSAvoidcalibration complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent replaces mechanical sensor installation through radial bores with an optical system where light sources and sensors are mounted on the casing surface, simplifying installation while the system's geometric relationships provide inherent calibration references that reduce calibration complexity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If traditional clearance measurement methods are used, then installation is straightforward, but measurement accuracy and efficiency deteriorate

Engineering Contradiction:

Improveinstallation simplicityVSAvoidclearance measurement accuracy

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent replaces traditional mechanical clearance measurement methods with an optical measurement system that uses light transmission and interruption detection to precisely measure blade tip clearance, significantly improving measurement accuracy while maintaining installation simplicity through surface-mounted components

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes the periodic rotation of the compressor rotor to repeatedly present blade tips to the optical measurement paths, enabling continuous real-time clearance measurement throughout each rotation cycle and improving overall measurement efficiency

Inventive Principle:

Principle #19Periodic action

4Measurement precision

If optical measurement paths are positioned at multiple radial heights, then measurement comprehensiveness improves, but system complexity increases

Engineering Contradiction:

Improvemeasurement comprehensivenessVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the optical measurement system into multiple independent measurement paths positioned at different radial heights, each capable of measuring clearance at its specific location, allowing comprehensive coverage while maintaining modular simplicity where each path operates independently

Inventive Principle:

Principle #1Segmentation

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

The system provides accurate and efficient measurement of blade tip clearance and roundness, enabling real-time monitoring of changes and vibrations, thus improving compressor efficiency and reducing maintenance needs.

Implementation Method 1

The controller is configured to monitor one or more parameters between a rotor and a casing at least partially based on an interruption or a transmission of one or more paths of light from the plurality of light sources to the plurality of light sensors

Methodology Applied

Scientific EffectLight transmission and interruption detection: Light

Data Source

PatentUS11060847B2System and method for optical measurements in a rotary machine

Publication Date: 2021.07.13 GE INFRASTRUCTURE TECH LLC

AI summary

A system is provided with a measurement system having a plurality of light sources, a plurality of light sensors, and a controller coupled to the plurality of light sources and the plurality of light sensors. The controller is configured to monitor one or more parameters between a rotor and a casing at least partially based on an interruption or a transmission of one or more paths of light from the plurality of light sources to the plurality of light sensors.