Optical Thermal Profiling via Multi-Wavelength Light Pulses

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Solution Overview

Problem

Current methods for measuring temperature and molecular number density within thermal devices, such as boilers and reactors, are cumbersome and unable to provide a three-dimensional profile using a single opening, and existing optical methods lack the capability to measure both temperature and molecular number density simultaneously.

Innovation Solution

A method utilizing collimated light pulses and absorption measurements at multiple wavelengths to determine temperature and molecular number density as a function of distance, allowing for a spatial profile to be obtained through a single optical inlet and enabling three-dimensional profiling by varying the direction of light pulses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple thermal sensors are inserted in various locations in the thermal device, then temperature measurement capability is improved, but maintenance burden and device complexity increase significantly

Engineering Contradiction:
Improvetemperature measurement capabilityVSAvoidmaintenance burden
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical thermal sensors with an optical measurement system that uses light pulses to measure temperature and molecular number density. The optical system includes a light source, optical inlet, and detector that work together to obtain temperature profiles without physical contact, thereby eliminating the maintenance burden associated with multiple thermal sensors while maintaining measurement capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The optical measurement system serves multiple functions: it measures both temperature and molecular number density simultaneously, and can obtain one-dimensional, two-dimensional, or three-dimensional profiles depending on the measurement configuration. This multi-functionality replaces what would traditionally require multiple specialized sensors for different measurement types.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of operation

If acoustical or optical methods are used for determining temperature, then maintenance burden is reduced, but the ability to measure three-dimensional profiles through a single opening is lost

Engineering Contradiction:
Improvemaintenance burden reductionVSAvoidthree-dimensional profile measurement capability
Core Design Contradiction:
Ease of operationVSLoss of information

Solution Approach 1:

The patent achieves three-dimensional profile measurement by systematically varying the direction of light pulses in three-dimensional space. The measurement device includes means for varying the propagation direction of light pulses, allowing temperature and molecular number density to be measured along multiple lines of sight, which when combined, reconstruct a three-dimensional profile from a single optical inlet location.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The system dynamically adjusts the propagation direction of light pulses to scan through different spatial locations. The measurement device can change the direction of light pulses in real-time, enabling comprehensive three-dimensional sampling of the thermal device interior without requiring physical movement of the entire device or multiple fixed sensors.

Inventive Principle:
Principle #15Dynamics

3Object-affected harmful factors

If existing optical methods are used, then non-invasive measurement is achieved, but simultaneous measurement of both temperature and molecular number density is not possible

Engineering Contradiction:
Improvenon-invasive measurementVSAvoidsimultaneous temperature and molecular number density measurement
Core Design Contradiction:
Object-affected harmful factorsVSLoss of information

Solution Approach 1:

The optical spectrum is segmented into multiple wavelength bands, with at least one band sensitive to temperature and another band sensitive to molecular number density. By measuring absorption or scattering at different wavelength bands separately, the system can independently determine both temperature and molecular number density from the same non-invasive optical measurements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system exploits the wavelength-dependent nature of light-matter interactions by changing the wavelength parameter of the probe light. Different wavelength bands interact differently with the gas molecules - some bands are more sensitive to temperature effects while others are more sensitive to number density effects. By varying the wavelength and measuring the differential responses, both parameters can be simultaneously determined.

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 precise, non-invasive measurement of temperature and molecular number density within thermal devices, reducing operational burdens and providing comprehensive spatial data without the need for multiple sensors.

Implementation Method 1

molecules of the gaseous compound absorb light

Methodology Applied
Scientific EffectAbsorption: Absorption (EM radiation)

Implementation Method 2

particles scatter light pulses hitting the particles at various moments of time

Methodology Applied
Scientific EffectScattering: Scattering

Data Source

PatentEP2876430B1A method for measuring temperature and molecular number density of a gaseous compound from a thermal device, and a thermal system
Publication Date: 2020.09.02 VALMET TECH OY
  • EP2876430B1 patent drawingFigure 1a~1b
  • EP2876430B1 patent drawingFigure 1c~6b
  • EP2876430B1 patent drawingFigure 2a~2b

AI summary

A method for measuring, from a thermal device, temperature, molecular number density, and/or pressure of a gaseous compound as function of distance, the gaseous compound absorbing at least some light. The method comprises generating, for a first wavelength band and a second wavelength band, a pulse sequence comprising a light pulse or light pulses, guiding the pulse sequence into the thermal device, and measuring, as function of time, the intensity of the scattered light at the first wavelength band and at the second wavelength band. The method further comprises determining information indicative of the differential absorption between the two wavelengths bands using measured intensities and determining the temperature, the molecular number density, and/or the pressure of the gaseous compound using the information indicative of the differential absorption between the two wavelengths bands. A thermal system arranged to carry out the method.